RECOMMENDATIONS. 



Woolwich Dock- Yard, 17th April, 1851. 

These are to certify, that James Larkin was employed as 
leading man of brass founders, in the Steam-engine Factory of 
this Yard, from the 30th day of November, 184.0, to the 12th 
day of April, 1851. During the last 2 J years he has been under 
my superintendence, and his capability as a workman has been 
quite satisfactory to me. 

EOT. HUMPHREYS, 

Chief Engineer. 



Philadelphia, December 7, 1852. 
Gentlemen : 

Mr. James Larkin has been conductor of the Brass Foundry 
Department in our establishment for the last twelve months. 
We have every confidence in his ability, and consider him to be 
at the head of his profession. 

We have taken a cursory view over the work he is about pub- 
lishing, and feel fully satisfied that it is what is much needed in 
the Trade. It is a desirable work for the pocket — for the artist 
as well as the mechanic. 

Respectfully yours, &c, 

REANEY, NEAFIE & CO., 

Penn Works. 

P) 



ii RECOMMENDATIONS. 

Philadelphia, December 2, 1852. 

We have taken a hasty view of Mr. Larkin's "Brass and Iron 
Founder's Guide." It is a work much wanted, and would doubt- 
less meet a ready sale. 

Yours, most respectfully, 

MERRICK & SON, 
Engineers, Mechanicians, Sfc. t Washington Street. 



Philadelphia, December 2,. 1852. 

I have had some conversation with Mr. James Larkin, and 
examined part of the manuscript of a work he intends publish- 
ing, viz. : " The Brass and Iron Founder's Pocket Guide," and 
I have reason to believe that it will be very useful to persons 
engaged in that branch of business. 

JOHN AG NEW, 
Franklin Works, Vine Street. 



Philadelpiha, December 3, 18-32. 

I have held some conversation, as well as examined the manu- 
script of a book which Mr. James Larkin is about publishing, 
upon the subject of Iron and Brass Founding, which I believe 
is a work much needed by those engaged in these branches of 
manufacture, and I feel it will prove a great desideratum for 

those so engaged. 

HENRY HOMER, 

Brass Founder, §c, 77 Race Street. 



THE PRACTICAL 



BRASS AND IRON FOUNDER'S 



GUIDE. 



THE 

PRACTICAL 

BRASS AND IRON FOUNDER'S 



o^rfo^; 



GUIDE: iAAaM y 

A CONCISE TREATISE 



ON THE ART OF 

BRASS FOUNDING, MOULDING, ETC. 

•WITH NUMEROUS 

PRACTICAL RULES, TABLES, AND RECEIPTS 



GOLD, SILVER, TIN, AND COPPER FOUNDING; PLUMBERS, BRONZE AND 
BELL FOUNDERS, JEWELLERS, ETC., ETC. 



BY JAMES IaRKIN, 

CONDUCTOR OF THE BRASS FOUNDRY DEPARTMENT IN REANET, NEAFIE & CO.'S 
PENN WORKS, PHILADELPHIA. 



PHILADELPHIA: 
A. HART, late CAREY & HART, 

123 CHESTNUT STPvEET. 

1853. 




Entered, according to the Act of Congress, in the year 1853, by 

A. HART, 

in the Clerk's Office of the District Court of the United States, in and 
for the Eastern District of Pennsylvania. 



^-SW? 



E. B. MEARS, STEREOTYPER. T. K. & P. G. COLLINS, PRINTERS. 






PREFACE. 

The world at present groans under, a load of new 
publications on every branch of science and art; 
with which no former period of our literary annals 
can for a moment be compared. 

The most assiduous students, unable to peruse a 
thousandth part of the works which are daily soli- 
citing their attention, are quite perplexed and dis- 
tressed about what to choose and what to reject. 

This I have frequently found to be the case 
with myself, and while debating the question in 
my own mind, have lost, in doubt and uneasiness, 
the time I meant to set apart for practical manipu- 
lation. 

Impressed, therefore, with the unspeakable dis- 
advantages that result from the circumstances just 

(?) 



viii PREFACE. 

stated, and anxious to save others, in some degree, 
from that unpleasant dilemma in which I have 
myself been so often placed, I have resolved on 
the present publication, which I hope will to a 
very great extent accomplish the useful object I 
have in view. 

With what judgment, however, the design has 
been formed, and with what skill it has been exe- 
cuted, it becomes not me to determine — that ques- 
tion, to the result of which I am deeply alive, remains 
now with a higher tribunal. 

During the last fifteen years I have, from time 
to time, contributed papers to well known mechanical 
and philosophical publications, on subjects herein 
discussed. These I have carefully revised for the 
present work, and have added much information 
gleaned in the field of experience, and from the 
arcana of science. 

I would add in conclusion, that I have been 
practically employed in the business for thirty-four 
years, having conducted the work, in all its branches, 
at Messieurs Sandford et Varreles, Hue de Eoche- 
chourt, one of the largest ateliers in Paris, as well 



PREFACE. ix 

as at the British government works, steam-engine 
and ship-building yard, Woolwich, London, for the 
last eleven years — so that the reader may relieve 
himself of all doubt and difficulty in the matter. 

James Larkin. 

Philadelphia, 1853. 



CONTENTS. 

PACE 

On the Properties of the Metals . . . .19 

On Metallic Alloys ..... 32 

Table of Metals . . . . . .37 

Conducting Powers of Metals .... 38 

Table of Experimental Results as to some of the Chemical 
and Physical Properties of the Atomic Alloys of Copper 
and Zinc, and of Copper and Tin ... 40 

On Founding . . . . . .42 

On Brass Founding ..... 43 

Copper . . . . . . .45 

On the Reduction of Copper .... 46 

Tin ....... 47 

On the Reduction of Tin, Grain and Block Tin . 49 

On Zinc ....... 50 

On Lead ...... 51 

On Antimony . . . . . .52 

Order and Working of Metals .... 53 

On Copper and Tin . . . . .54 

Bronze for Cannon, Statues, &c. ... 55 

On Bell Metal . . . . . .55 

On Copper and Tin Mixtures .... 56 

Alloys of Copper and Zinc . . . . .57 

Alloys of Copper, Zinc, Tin, and Lead . . 59 

Manheim Gold . . . . . ,60 



(ID 



xu 



CONTENTS. 



Pinchbeck 

Princess Metal 

Tombac 

Artificial Gold 

Fine Brazing Solder 

Remarks 

Facing . 

Metallic Moulds 

Pewtering 

Complex Objects 

On Bell Founding 

On'Gun Founding . 

On Figure Casting 

Brass Mirrors 

Copper . 

Metals 

Surface of Metals 

Blanched Copper 

British Weapons and Tools in Bronze, anciently called Co- 
rinthian and Syracuse Brass 

On Brass ....... 

Casting in Plaster ..... 

To Transfer Engravings to Plaster Casts . 

To Varnish Plaster Casts .... 

To Cast Concave or Convex Moulds of Medals on Tin-Foil, 
with Plaster ...... 

To Cast Vegetables, Insects, Small Birds, Frogs, Fish, &c, 
in Plaster Moulds ..... 

To Prepare a Metal for the Above . 

Sir Isaac Newton's Fusible Metal 

Rose's Alloy ...... 



PAGE 

60 
61 
61 
61 
61 
62 
63 
64 
65 
66 
67 
68 
70 
72 
72 
72 
73 
73 



CONTENTS. xiii 

PAGE 

Dr. Dalton's Fusible Alloy .... 80 

To Cast in Wax . . . . . .81 

To Cast in Sulphur ..... 82 

To Cast in Glue . . . . . .83 

To make a Fine Glue, wherewith you may cast Curious 

Medals . . . . . . .83 

To Cast in Bread Paste .... 84 

To Cast Figures in Imitation of Ivory . . .85 

Rice Glue Statuary ..... 85 

A Composition for Ornaments . . . .86 

Alloys, Amalgams, &c. .... 87 

Native Alloys . . . . . .88 

Density of Metals ..... 89 

Bronze, Bell, and Speculum Metals . , .90 

Combination and Chemical Action ... 91 

Yellow Brass . . . . . .92 

To make Copper Medals and Medallions . . 93 

Amalgamation of Metals . . . . .94 

Bismuth ...... 97 

On Friction . . . . . .98 

On Bells ...... 100 

On Fluxes . . . . . . .101 

Fusing and Melting Points . . . .103 

Fluidity . . . . . . .104 

Anti-Friction Metals . ... 105 

Table for Converting Decimal Proportions into Divisions of 

the Pound Avordupois .... 106 

Keller's Statue Composition .... 107 

The Chinese Packfong . . . . .108 

Copper . . . . . . .108 

Silver Steel . . . . . .109 

9 



XIV 



CONTENTS. 



Copper and Antimony 

Antimony and Tin, Copper and Bismuth 

Bismuth and Lead . 

Full Measure of Capacity of Tin and Lead 

Brilliants of Fahlun 

Queen's Metal . 

Tin and Zinc 

Tin and Iron 

To Silver Copper 

Mosaic Gold 

To Bronze Brass, &c. 

Lacquers 

Green Bronze Liquid 

To Silver Ivory 

Zincing 

Metal Plates 

Cast Metal Balls 

Cast Iron Pipes 

Cast Metal Cylinders 

Specific Gravity and Weight of Materials 

Specific Cohesion and Strength of Metals 

Direct Cohesion of Metals 

Resistance of Metals to Pressure . 

Resistance of Metals to Torsion 

Gold and Silver Solders 

Brass Solder • 

Method of Soldering Gold and Silver 

To Cleanse Silver after it is Soldered . 

Silver Solder for Jewellers . 

Trinket Composition 

Silver-Plate and Medal Alloy 



CONTENTS. 



xv 



Gold Coin of America Alloy- 
Solder for Iron 

Soldering and Burning Metals 

Plumber's Solder . 

Compositions of Pewter 

White Metal 

Mosaic Mixture 

Silvery-Looking Metal 

Metal for Flute Valve Keys 

German Titanium . 

Spanish Titanium 

Britannia Metal 

Columbia Metal 

Type Metal 

German Silver . 

Speculum Metal 

Remarks 

Platina 

On the Properties of Arsenic 

Fontainemoreau's New Alloys 
Bronze, Copper, and Brass 

On Zinc as a Protective Covering for Iron ; and the Adap- 
tation of the Process of Electro-Deposition for that Pur- 
pose .....•• 

Water in Pipes ....•• 

On Crucibles ..•••-• 

Plumbago .....•• 

Hardening Steel ..... 

On Boron ....••• 

On Sulphur ...... 

Selenium .....•• 



of Zinc, a substitute for 



PAGE 

129 
129 
130 
135 
135 
135 
136 
136 
136 
136 
137 
137 
138 
138 
139 
140 
142 
144 
145 

147 



152 
162 
163 
166 
167 
167 
170 
172 



xvi CONTENTS. 

PAfiE 

On Chlorine . . . . . .373 

Metallic Oxides . . . . . .175 

Appendix ...... 177 

To Brown Gun Barrels . . . . .179 

Varnish for Gun Barrels that have undergone the Process 

of Browning . . . . . .180 

Ethereal Solution of Gold . . . .180 

To Coat Small Nails, &c, with Tin ... 181 

Bronzing Electrotype Casts — Chemical Bronze . 182 

Black Lead Bronze ...... 184 

Carbonate of Iron Bronze .... 185 

To Tin Iron . . . . . .185 

Liquid Glue 180 

Artificial Fire-Clay . . . . . .186 

A Cement which Resists the Action of Fire and "Water 187 

Cement for the Joints of Cast Iron . . . 188 

Niello-Metallic Ornaments . . . .188 

Tracing Paper . . . . . .189 

To Fix Drawings . . . . .190 

Antidote to Arsenic . . . . .191 

To Soften Ivory ..... 191 

To Separate the Metallic Portion from Gold and Silver 

Lace ....... 191 

Blueing and Gilding Steel . . . . .192 

To Harden Steel Dies ..... 193 

Portable Glue . . . . . .194 

Prevention of Corrosion .... 194 

Cement . . * . . . .195 

Soluble Glass ...... 195 

Japanning . . . . . . .196 

To Preserve Polished Steel from Rust . . 198 





CONTENTS. 


xvii 

PAGE 


Cement for Attaching 


Metal to Glass 


. 198 


Varnish for Coloured Drawings 


199 


Japanners' Copal Varnish . 


. 199 


Soft Varnish 


. 


199 


Hard Varnish 


. 


. 200 


Flexible Varnish 


. 


200 


French Polish 


. 


. 200 


Brunswick Black 


. 


201 


Mordant Varnish 


. 


. 201 


Another 


. 


202 


Another 


. 


. 202 


Another 


. . 


202 


Another , 


. 


. 203 


Superior Green Transparent Varnish . 


203 


Etching Varnish 


. 


. 204 



2* 



BRASS AND IRON FOUNDER'S GUIDE. 



ON THE PROPERTIES OF THE METALS. 

The metals constitute by far the most numerous 
class of undecompounded bodies in chemical arrange- 
ments. They are, in general, readily distinguished 
from other substances, by characters which every 
one recognises ; but to an ordinary observer they do 
not appear to differ essentially from one another; 
they seem rather to owe their differences of colour, 
and other physical properties, to a tinge and cha- 
racter given to them by adventitious circumstances, 
and perhaps some trifling admixture of other sub- 
stances. This opinion is natural, and was at one 
time the prevailing doctrine of the learned. 

When chemistry began to be developed in the 

hands of the alchemists — upon whom it has been 

fashionable to heap ridicule for the extravagances 

of their notions — it was generally admitted that all 

(19) 



20 PROrERTIES OF THE METALS. 

metals were essentially the same ; and as gold was 
reckoned the most precious, it was assumed to be 
the pure basis of all the other metals. Upon this 
assumption, the aim of alchemy was direct and ra- 
tional; its object was to separate the substance, 
whatever it might be, the presence of which pre- 
vented lead and other base metals from being gold. 

It is hardly necessary to observe that these efforts 
failed. Accordingly modern chemists, taught by 
experience to believe the required decomposition 
impossible, have come to the matter-of-fact conclu- 
sion that when metals are of different colours, degrees 
of hardness, lustre, ductility, fusibility, and so on, 
that they are of different natures. 

Although the metallic character be readily and 
popularly recognised, it is difficult to define it with 
accuracy. 

With the single exception of quicksilver, the 
metals are all solid at ordinary atmospheric tem- 
peratures ; but their most striking property is their 
lustre, which is so remarkable as to be at once 
understood by the expression, metallic lustre. This 
property belongs, in a greater or less degree, to 
every metal : it is the property of strongly reflect- 
ing light, and seems connected with a certain state 
of aggregation of the metallic particles. The same 



PROPERTIES OF THE METALS. 21 

property is however possessed, at least superficially, 
in a minor degree, by mica, animal charcoal, 
silenium, and polished indigo — bodies not at all 
metallic. 

In consequence of the peculiar power of the 
metals to reflect light, they are no less remarkable 
for their opacity than their lustre. Thus, silver- 
leaf, only one hundred-thousandth of an inch in 
thickness, is perfectly opaque ; and leaves of other 
metals, in general, allow no light to pass through 
their substance. Yet gold-leaf, of the two hundred- 
thousandth part of an inch in thickness, would seem, 
as observed by Sir Isaac Newton, to transmit green 
rays of light; and it is probable that, could we 
obtain films of other metals of equal thinness, they 
would be found to allow certain rays to pass through 
them. The fact, as observed with gold, has how- 
ever been ascribed to the porosity of the metal, the 
rays transmitted passing through an infinite number 
of minute fissures in the thin leaf. This, it must 
be admitted, is quite compatible with perfect opacity 
of the substance of the metal ; the leaf, like a piece 
of wire gauze, allowing the light to pass only through 
its interstices, and not through the solid metal itself, 
which may be perfectly impervious to all luminous 
rays. 



22 PROPERTIES OF THE METALS. 

The polished metals are imperfect radiators and 
receivers of heat, but they are excellent reflectors, 
both of light and heat : hence their peculiar fitness 
for the construction of mirrors. They are also, in 
general, excellent conductors of heat, and most of 
them also of electricity, though probably not all. 
The greater number of them are susceptible of 
assuming the crystalline form. With several of 
them this may be effected by fusion and slow 
cooling. Thus, by suffering the melted metal in 
a crucible slowly to concrete externally, and then 
perforating the solid crust, and pouring out the 
liquid interior, the cavity so formed will be found 
lined with crystals. 

When a metal is precipitated by another, it is 
often deposited in a crystalline state. Thus, if a 
little mercury be thrown into a solution of nitrate 
of silver (lunar caustic), the silver is precipitated in 
beautiful crystals. The same phenomenon occurs, 
when a bit of zinc is suspended in a salt of lead. 
In like manner, if a stick of phosphorus be immersed 
in a silver solution, it becomes incrusted with beau- 
tiful metallic crystals, which after some time per- 
fectly encase the phosphorus. Gold is also some- 
times deposited in crystals from its ether solutions ; 
and during the decomposition of several of the 



PROPERTIES OF THE METALS. 23 

metallic solutions, by galvanic electricity, especially 
when low powers are employed, beautiful metallic 
crystals are often obtained. This is readily verified 
with solutions of copper and silver salts. 

The metals possess, in different degrees, a pecu- 
liar tenacity, which, in its greatest perfection, ren- 
ders them malleable and ductile — that is, capable 
of being extended under the hammer, and drawn 
into wire — properties which belong to no other 
species of matter. Thus, gold and silver may be 
beaten into leaves almost inconceivably thin ; cop- 
per, tin, platinum, and lead, possess the same pro- 
perty, but less perfectly ; others are entirely desti- 
tute of it, as arsenic, antimony, and cobalt. These 
last can indeed be readily reduced to fine powder, 
and hence they are distinguished as brittle metals. 

Those metals which are malleable are also ductile ; 
these properties are analogous, but do not appear 
to bear a uniform relation to each other, among the 
metals possessing them. Gold and silver are, how- 
ever, the most ductile, as they are the most malle- 
able. Thus, a grain of gold may be extended by 
hammering, so as to cover fifty-two square inches of 
surface, or it may be drawn into 500 feet of wire, 
and by enveloping it in silver, it may be extended to 
700 feet. In like manner, platinum, which is in- 



24 



PROPERTIES OF THE METALS. 



ferior to copper and tin in malleability, lias been 
drawn into wire not more than the 3ogot»th of an 
inch diameter — a degree of fineness, which, except 
under certain circumstances of illumination, is in- 
visible. Iron may be drawn into wire as fine as the 
human hair; copper is less ductile, and zinc, tin, 
and lead, can be drawn into wire, but considerably 
less fine. The brittle metals, as might be supposed, 
do not draw. 

The following table shows the order which the 
metals bear to one another, in respect to these pro- 
perties : — 



A TABLE SHOWING THE OR/DEE. WHICH THE METALS BEAR TO ONE 
ANOTHER IN RESPECT TO THEIR PROPERTIES : — 



Order of Malle- 
ability. 


Order of Ductility. Order of Tenacity. 


Order of Brittle- 
ness. 


Gold, 


Gold, 


Iron . .1000 


Antimony, 


Silver, 


Silver, 


Copper 550 


Arsenic, 


Copper, 


Platinum, 


Platinum 494 


Bismuth, 


Tin, 


Iron, 


Silver . . 349 


Cerium, 


Cadmium, 


Copper, 


Gold . . 273 


Chromium, 


Platinum, 


Zinc, 


Zinc . . 199 


Cobalt, 


Lead, 


Tin, 


Tin . . . 63 


Columbium, 


Zinc, 


Lead, 


Lead . . 50 


Manganese, 


Iron, 


Nickel, 




Molybdenum, 




Nickel, 
Palladium, 


Palladium, 
Cadmium, 


Iron wire 1-tenth in. 
diameter is capable 
of sustaining 5001bs. 


Tellurium, 
Titanium, 


Potassium, 




avoirdupois. 


Tungsten, 


Sodium, 






Uranium, 


Solid mercury, 






Rhodium. 



PROPERTIES OF THE METALS. 



25 



are scratched by calc-spar. 



Few of the metals when pure are very hard, and 
some are so soft as to yield to the nail. The fol- 
lowing table of hardness is given from the experi- 
ments of M. Dumas : — 

Titanium, 

Tungsten, ? are harder than steel. 

Manganese, 

Platinum, 

Palladium, 

Copper, 

Gold, 

Silver, 

Tellurium, 

Bismuth, 

Cadmium, 

Tin, 

Chromium, 

Rhodium, 

Nickel, 

Cobalt, 

Iron, 

Antimony, 

Zinc, 

Lead yields to the nail. 

Potassium, 

Sodium- 



scratch glass. 



are scratched by glass. 



are soft as wax at 60°. 



Mercury is liquid above minus 39°. 



26 PROPERTIES OF THE METALS. 

In respect to fusibility — that is, the capability of 
being melted by heat — the metals differ from each 
other as widely as in any other respect. Thus, mer- 
cury requires to be cooled down to minus 39° before 
it becomes solid, whereas the melting point of pla- 
tinum is somewhere beyond 3280°. Potassium melts 
at 140°, and sodium at 190°. Tin becomes liquid 
at 444°, bismuth at 500°, lead at 600°, zinc at 770°, 
and antimony at 800°. Silver, gold, and copper, 
require a bright cherry-red heat to melt them (about 
2000°) ; cast iron, nickel, and cobalt, a white heat 
(about 2800°) ; and manganese, and malleable iron, 
the highest heat of a smith's forge (about 3000°). 
The highest temperatures of our furnaces are only 
sufficient to agglutinate very imperfectly the metals 
molybdenum, uranium, tungsten, and chromium ; 
and titanium, cerium, osmium, iridium, rhodium, 
platinum, and columbium, require the intense heat 
of the oxy-hydrogen blow-pipe, or that of voltaic 
electricity, to fuse them. Some of the metals, when 
exposed to heat, not only melt, but, obeying the 
general law of liquids, boil and evaporate when the 
heat is sufficiently high. Thus, mercury, zinc, cad- 
mium, bismuth, tellurium, and antimony, boil and 
evaporate at a red heat ; and, in a vacuum, mercury 
is known to evaporate at ordinary atmospheric tem- 



PROPERTIES OF THE METALS. 27 

peratures (above 50°) ; silver and lead require a 
high heat to vaporize them ; tin a still higher heat ; 
and gold will only evaporate slowly under the most 
intense heat that can be applied. Several of the 
other metals, as iron and nickel, cannot be made to 
evaporate in the most intense heat with which we 
are acquainted. Arsenic, on the other hand, eva- 
porates without melting. 

There are several of the metals which emit a pecu- 
liar odour, especially when rubbed, or have their 
temperature slightly raised. This is particularly the 
case with copper, iron, and tin. The vapour of 
others is very remarkable. The arsenic vapour has 
the smell of garlic; that of tellurium smells like 
horseradish ; and osmium takes its name from the 
smell of its vapour (osme, odour). Some of the 
metals have also a peculiar taste when applied to the 
tonsue, which has been ascribed to their electrical 
condition ; but it must be remarked that many of 
the most oxidable metals are entirely destitute both 
of taste and odour. 

A high specific gravity was reckoned one of the 
most marked characteristics of the metals, till the 
discovery of the metallic basis of the alkalies by 
Sir Humphrey Davy. So intimately indeed was the 
metallic lustre associated in the mind with great 



28 PROPERTIES OF THE METALS. 

weight, that when a piece of potassium was put, for 
the first time, into the hand of an eminent teacher 
of chemistry, in admiring its perfect metallic cha- 
racter, he poised it upon the finger, and exclaimed, 
" How heavy !" and the prejudice was only removed 
by seeing it float upon water. The list of metals, 
however, includes the densest forms of matter with 
which we are acquainted ; and, although great weight 
cannot be regarded as a universal property, we hare 
few examples in which the density is less than the 
density of water. These examples comprehend only 
potassium and sodium ; all other metals are of 
greater specific gravity, up to platinum, which is 
twenty-one times the weight of an equal bulk of 
water. 

The degrees of facility with which the metals 
combine with oxygen differ widely. Some, by mere 
exposure to the atmosphere, absorb its oxygen with 
great rapidity : such is the case with potassium and 
sodium : others absorb it more slowly, as manganese, 
iron, and arsenic ; and lead and copper still more 
slowly. Others, again, do not oxidate by exposure 
to air, unless at a high temperature ; this is the case 
with tin, zinc, mercury, antimony, bismuth, and 
cobalt, which absorb the oxygen readily when in a 



PROPERTIES OF THE METALS. 29 

state of fusion. Others, again, do not oxidate by- 
exposure to air and heat, or by immersion in water, 
as gold and platinum ; the same is nearly true of 
nickel and silver. The tendency of the metals to 
combine with oxygen appears, however, to be greatly 
influenced by their mechanical condition ; for some 
of them, which are only slowly oxidized by expo- 
sure to air and heat, are rapidly acted upon when 
in very fine mechanical division, even at common 
temperatures. 

In combining with oxygen under heat, some of 
the metals burn with great splendour : this is exem- 
plified in copper, zinc, tin, and bismuth. Iron filings, 
when thrown even into the flame of a candle, and 
very fine iron wire, when held in the external part 
of the flame, take fire and throw off beautiful scin- 
tillations. Antimony burns at a white heat, and 
tellurium burns before the flame of the blow-pipe. 
In short, at intense heats most of the metals may 
be burned, and, if placed in the flame of the oxy- 
hydrogen blow-pipe, they deflagrate with intense 
brilliancy and great facility. 

On the other hand, potassium burns by contact 

with a piece of ice, with as much intensity as others 

do in the oxy-hydrogen flame. 
3* 



30 PROPERTIES OF THE METALS. 

The metals, by combination -with oxygen, lose 
their metallic characters, and form an important 
series of definite compounds known as the metallic 
oxides. These have very different characters and pro- 
perties ; even the same metal not unfrequently affords 
oxides which differ from each other widely in pro- 
perties and appearance. Thus fifty parts of mercury, 
combining with one part of oxygen, produces a black 
oxide, and with two parts of oxygen, the oxide is 
red and highly poisonous. Many of the metals 
thus afford more than one oxide ; and it is to be 
observed, that when the same metal unites in more 
than one proportion with oxygen, the oxygen in the 
second and higher oxides bears a definite arith- 
metical relation to the first ; and when two oxides 
are thus formed, that having the minimum of oxy- 
gen is termed the protoxide, and that with the 
maximum of oxygen the peroxide. This law of 
definite proportions will be explained hereafter. 

Among the combinations of metals with oxygen, 
some are soluble in water and alkaline, such as the 
fixed alkalies, soda, potash, and lithia, and the 
alkaline earths ; others are soluble and sour, form- 
ing the metallic acids. Some are insoluble in water, 
and have neither taste nor smell ; and many when 



TROrERTIES OF THE METALS. 31 

taken into the stomach act as poisons. Thus, oxide 
of arsenic is a notorious and virulent poison ; oxide 
of copper is less virulent than arsenic ; oxide of 
lead is a painful poison ; oxide of nickel is also 
destructive of life ; and the peroxide of mercury, 
unless in small quantities, is likewise poisonous. 



32 TROrERTIES OF THE METALS. 



ON METALLIC ALLOYS. 

The metals, for the most part, may be combined 
with each other, forming a most important class of 
compounds, known as the metallic alloys: Many 
of these are more useful than the metals of which 
they are composed, and possess properties a good 
deal different from their elements. One of the best 
known and most serviceable of all the alloys is brass, 
a compound of zinc and copper : it is harder, more 
easily melted, more close in the texture, better 
coloured, and less liable to tarnish than copper ; it 
is less brittle, and in every way more valuable than 
zinc. Pinchbeck is composed of the same ingre- 
dients as brass, but in different proportions, the 
zinc predominating. Copper and tin are two very 
soft and flexible metals, which, being fused together, 
form the alloy known as bell-metal, which is harder 
than iron, very brittle, and very sonorous. The 
same materials, in different proportions, form spe- 
culum metal, and the kind of ordnance improperly 
called brass cannon. Pewter is composed of tin 
and lead, sometimes with the addition of zinc, cop- 
per, or bismuth. 



ON METALLIC ALLOYS. 33 

Plates upon which music is stamped are composed 
of tin and antimony ; and printing types are formed 
of an alloy of lead and antimony, with a slight ad- 
dition of bismuth. Tin-foil is an alloy of tin and 
lead ; and plumbers' solder is composed of the same 
metals. Fusible metal is a compound of bismuth, 
lead, and tin, with sometimes a little mercury. 

An amalgam of zinc and mercury is used for ex- 
citing electric machines, and that of mercury and 
tin is the compound employed for silvering looking- 
glasses. Gold coin is an alloy of gold and copper, 
in the proportion of 11 to 1 ; and jewellers' gold is 
an alloy of the same metals in the proportion of 3 of 
gold to 1 of copper. Green gold has silver instead 
of copper. Silver coin, in like manner, is an alloy 
of silver and copper in the proportion of 37 to 3. 
These alloys of gold and silver are harder, and 
consequently less liable to wear than the pure 
metals. 

It is worthy of remark, that in the formation of 
alloys, the metals in the act of combination gene- 
rally evolve heat. For instance, when platinum and 
tin-foil are fused together, there is the most vivid 
ignition ; and when zinc and copper are suddenly 
mixed, in the proportion to form brass, the increase 
of heat is such as to vaporize part of the metal. 



34 PROPERTIES OF THE METALS. 

The alloys are formed by various processes, de- 
pending upon the nature of the metals employed. 
Most of them are prepared by simply fusing the 
two metals together ; but if there be a considerable 
difference in their specific gravities, the heavier 
very generally subsides, and the lower part of the 
mass thus differs in composition from the upper. 
This may be in a great measure prevented by agi- 
tating the alloy till it solidifies, but this is not 
always convenient. Thus, in stereotype plates 
which are cast vertically, the upper side usually 
contains more antimony than the other. The same 
is observed when an alloy of gold and copper is cast 
into bars ; the mould being placed perpendicularly, 
the upper part of the bar contains more copper than 
the lower. Copper and silver evince the same ten- 
dency to separate; although they appear readily to 
combine, it is found extremely difficult to form a 
bar of their alloy of perfectly uniform composition 
throughout. Many of the alloys, however, appear 
to be true chemical compounds ; and in some cases 
the metals unite in definite proportions only. 

It is indeed not improbable that wherever metals 
do form alloys, that the alloys so formed are definite 
compounds, and that any undue quantity of either 
metal present, simply mixes mechanically with the 



ON METALLIC ALLOYS. 35 

mass. Thus, among the artificial as "well as natural 
alloys, there are many which crystallize ; and in 
some cases, the true compound may be separated 
from the mere mixture of the superfluous metal by 
the process of crystallization. 

The tendency of the metals to unite with other 
elements, and with each other, prevents their being 
often found disseminated in mineral nature, in their 
pure metallic state. 

Some of them do occur so nearly pure as to be 
called native metals. Thus gold is found only 
slightly alloyed with silver and copper, and pla- 
tinum occurs as an alloy of iron, palladium, iridium, 
rhodium, and osmium. Silver, copper, mercury, 
antimony, bismuth, arsenic, and tellurium, occur 
both in the native metallic state, although never 
absolutely pure, and mineralized with other bodies. 
Lead, tin, zinc, iron, antimony, and several others, 
are extensively disseminated as sulphurcts, that is, 
combined or mineralized by sulphur. 

The combination of a metal with its mineralizing 
substance, is what we denominate an ore; and it is in 
this state of ore that metals occur, when they are not 
found native. The ores are exceedingly diversified 
in appearance ; sometimes they possess metallic 



36 PROPERTIES OF THE METALS. 

lustre ; sometimes they appear stony, at other times 
earthy. In some instances they are crystallized 
into regular forms, but more commonly they occur 
in shapeless masses. The ores are chiefly found in 
veins — that is, large fissures of rock, especially the 
granitic, schistous, and limestone rocks; but some- 
times they are found in rounded and detached frag- 
ments, disseminated through certain alluvial and 
diluvial strata of the earth. The extraction of the 
metal from them is denominated their reduction, 
and implies a laborious series of operations, me- 
chanical and chemical, comprehended under the 
term metallurgy. 



TABLE OF METALS. 



37 



The following table contains an enumeration of 
the metals, and may be useful for reference. The 
column headed "equivalents," shows the weight 
which unites with 8 oxygen to form the oxides, and 
the succeeding column contains the symbols by which 
the metals are denoted in systematic chemistry. 



Names of Metals. 



1. Gold (Aurum) . . . .' 

2. Silver (Argentum) . . . 

3. Iron (Ferrum) .... 

4. Copper (Cuprum) . . , 

5. Mercury (Hydrargyrum) 

6. Lead (Plumbum) . . . 

7. Tiu (Starmum) . . . , 

8. Antimony (Stibium) . . ' 

9. Bismuth 

jlO. Zinc 

111. Arsenic "| 

12. Cobalt j 

13. Platinum 

14. Nickel 

15. Manganese 

16. Tungsten (Wolfram) . . 

17. Tellurium 

18. Molybdenum 

19. Uranium 

20. Titanium 

21. Chromium 

22. Columbium (Tantalum) . 

23. Palladium , . . . . 

24. Rhodium 

25. Iridium 

26. Osmium 

27. Cerium 

28. Potassium (Kalium) . 

29. Sodium (Natronium) . 

30. Barium 

31. Strontium 

32. Calcium 

33. Cadmium 

34. Lithium 

35. Silicium 

36. Zirconium . . . • . 

37. Aluminum .... 

38. Glucinum 

39. Yttrium 

40. Thorium 

11. Magnesium .... 

42. Vanadium 

43. Lantanum 



Authors, and Dates of 
their Discovery. 



Known to the 
ancients. 



Basil Valentine 1490 
Agricola . . 1530 
Paracelsus? . 1530 



Brandt 

Wood . . 
Cronstedt . 
Gahn . . 
D'Elhuiart 
Muller . . 
Hielm . . 
Klaproth . 
Gregor . . 
Vauquelin 
Hatchctt . 

Wollaston 

Tennant . 
Hisinger . 



1733 

1741 
1751 
1774 
1781 
1782 
1782 
1789 
1791 
1797 
1S02 

1803 

1803 
1804 



Davy . . . 1S07 



Stromeyer . 1818 
Arfsvvedson . 1818 



. 1824 

. 1828 

. 1829 

. 1829 

. 1830 

. 1840 



Berzelius . 

Wohler . 

Berzelius . 
Bussy . . 

Seftstrom . 
Mosander 



Specific 

Gravity. 



f 19.25 

10.47 

7.78 

8.89 

13.56 

11.35 

7.29 

" 6.70 

9.80 

7.00 

f 5.88 

( 8.53 

20.98 

8.27 

6.85 

17.60 

6.11 

7.40 

9.00 

5.30 



11.50 



0.86 
0.97 



8.60 



Melting 
Points. 



Falir. 

2016 3 

1873 

*2S00? 

1996 

—39 

612 

442 

497 

773 

2810? 

oh. bp.f 

2810? 

s. f. * 

620? 

ohbp 

ohbp 

ohbp 

ohbp 

oh%p 

ohbp 
fohbp 
(ohbp 

136 
190 



442 



Equ. 
Hyd. 
= 1. 



200 

108 
28 
64 

200 

104 
58 
65 
72 
32 
38 
30 
99 
30 
28 

100 
32 
48 

217 
24 
28 

185 
54 
52 
99 

100 
48 
40 
24 
70 
44 
20 
56 
8 
8 
33 
14 
18 
32 
60 
13 
69 
? 



Syni, 



Au. 

Ag. 

Fe. 

Cu. 

Hg. 

Pb. 

Sn. 

Sb. 

Bi. 

Z. 

Ar. 

Co. 

PI. 

Ni. 

Mn. 

W. 

Te. 

Mo. 

U. 

Ti. 

Cr/ 

T. 

Pd. 

R. 

Ir. 

Os. 

Ce. 

K. 

Na. 

Ba. 

Sr. 

Ca. 

Cd. 

L. 

S. 

Zr. 

Al. 

Gl. 

Y. 

Th. 

Mg. 

V. 

Ln. 



Smith's forge. 



f Oxy-hydrogen blowpipe. 



38 



CONDUCTING TOWERS OF METALS. 



ON THE CONDUCTING POWERS OF VARIOUS METALS 
FOR VOLTAIC ELECTRICITY. 



The researches of Pouillet have thrown much 
light upon our knowledge of the conducting powers 
of various bodies for voltaic electricity, and the 
results he has arrived at enable him to express the 
relative conducting powers of the different metals 
by the following numbers : — 



Palladium 






5791 


Silver 






5152 


Gold . 






3975 


Copper . 






3838 


Platinum 






855 


Bismuth 






38-1 


Brass from 






900 to 200 


Cast steel from 






800 to 500 


Iron 






600 


Mercury 






100 



The resistance of metals to conduction of electri- 
city has been accurately ascertained by means of 
the degrees of heat evolved by the passage of a 
current of equal intensity through different metals ; 



CONDUCTING POWERS OF METALS. 



39 



the heat developed in conducting wires is in propor- 
tion to the extent of surface of the positive plate, 
no matter whether the current emanate from a sin- 
gle cell or a series of cells. The following table 
shows the degrees of heat evolved by an equal cur- 
rent from different metals, measured by the pressure 
of expanded air upon a column of alcohol : 



Metals. 


Heat Evolved. 


Resistance. 


Silver .... 


6 


1 


Copper .... 


6 


1 


Gold .... 


9 


n 


Zinc .... 


18 


3 


Platinum 


30 


5 


Iron ..... 


30 


5 


Tin ... 


36 


6 


Lead .... 


72 


12 


Brass .... 


18 


3 



It is apparent that the conducting powers of the 
above metals are inversely as these numbers. Sil- 
ver being a better conductor than lead, in the 
ratio of 12 to 1. 



(40) 



O J 



d a" -■ S js 
E £ 5 £ P 

S s S s 3 



o -o 

•ll 



•aonasaad 

•aatiosa.ul .naq} -ipqj oi noq.u. 

in noq.u "jajE^ i!og 'jajB^y. Eas n ! noaj 

m noaj isbq jo uoisoj-ioo ?sbq jo notsoaaog aq:> 

aqt asBaaon; sionv asaqj nV asuojoap s.Co[iv asaqi HV 



e — 



53 »"*■ gd 

S l. C as 3 " 
~ c S9«>2 
C 5 S r, ft H 



_■ — 



o5 



j§ pq t/j 

-^ ~£ -2 «5 ^ « h « SJ ?3 *" 



r. 



C N li 



CD O CU Sh 



£ -2 s 

'Is "S ® 
w . . 

a a> to 
£ S =3 p 2 



WQQjfqe! t>r-r*i 



•An 

I -TQIsn^ jo .lapjQ 



lO-tMINHOfflceNOOffliOiOiOiOOiOiOitWINH 



•o?y 'ssan 
-pjBH JO aapJQ 



ciHoo>cet-«u5-tnc'ioooi-coo»HN'*Hn 



•ojiaquajqc^ 

069 W Aniq 

-■B811EK jo aapjQ 



•Aim 

-ona jo japjQ 



OOC^flCliOplt-OMMHOOOOOOOOOOi 

1-1 TH I-l 



•snoj, ttt qoni 
aatmbs jad 'nois 
-aqoo aysiapui 



CO H iO CO (M_ H t-; b; H "O IN CO H CI t-; <N <3> 00 O) r-j Oi 00 CI 

•t CS1 H «' «'•*'«'♦ C3 N »' ffl «' C-l O CO O O id N ri ri iO 
<N r-t i-l r-l r-l r-l tH r-l i-l rH t-I r-i 



■OOOOlii 

o p4 &; &,' p^ 



dijd>-c5d 



ooooo 

&J fci &I 5q H 



rH OJ CO ■* CO CN r-l r-l CN i-t CN CO CO <N iH •<# r-l CM 
£ g £ |f J-J^ 

o o o p a s 



K ^= P5 r-l ^1 

4) 0) O O _, 
, t*j 0^ !>» >%J3 

; ^ ^ ,« J .2 

! X V. GO OQ j; 

' '-3 '-3 '-3 '-3 o 

I T3 -O xJ tS 55 



£ ? 



IfSil 



a o i o s 



« "3 "o P * 
-^ zi rj ® > 

S 3 S "J s 
Ph Eh fc ft co 






ogpaclg 



MOt-MNHiOSOl-OOMH^ 
O O O CO OC O H-f S Ci CO 00 01 c 
ffl O O CO iO iO ■* ■* M CI PI « 1-. ( 

ooccoo'ooccooccoooccooooot^i 



' o m » ?) n o h m in 

lHCuOCf-t-l , l-; C33 
jpCOOOOT^r-jHCO'-DOC 

• QO t^ co t-^ t-^ i-^ t- !C* to 



"X SB 

na^j Smaq naS 

-oap-VH •lU-'ioji 

ounojy 



| to 



cocob;H^c9Mt^Hioqc<jaoiir5ccH^h.iqoqHco 
t-< go o id cd rH o co t^ id co co r-5 -$ r d cr t-j co id oo o co oi 

CO ■* H CO O Ol 05 O Ol OwOlO CO tC CI CO CO ~ 01 » Oa 01 
COCOCNCNCNr-lr-liH « 00 00 K O CB * H H H 



JWUUi — » l - 1 v_< uj .-! '.^^ '_'J »x^ ^.' '^ ^'j yu w w n ^. ' . U ^^ 

co cn co co Ci cs co -* co o i-; ■* i- co oo CJs i- to ic co q q 

d o h oi -^ to © id co' o' t-5 co' cd o' i-J oi co -+' id o" cd o 

HHrlHHCMlNCOiOtOtCtOl-l>l^HWt^OOXo 



+ + " 



- + + + + 



OOOOOOOfliOMCCbiOClOt-fN-MOOOH _ 

ONccNi-oooKjH-fcoionHHO'Mnotoo 



NNNNNbJNNNNNNNSNSSNNSN^ 



+ + + - 



oooooooooooocoocoooooo 

©®aot-coio-*cocN cocooooooococo 



•}U.ilu;.i,)clxa HNN^IiOtOS»OOnONeO-*iOesx-. OHflM 

JO 'OX HHHHHHr|rlHrt«NtNN 



(41) 



o?2a« 



•uix 0} anp si 

aseajoni ntntaixura aqj 

'. aonosaad Jioqj n'i 'noaj js-bq 

no jajB^i rcasjo notjoB saisojjoo 

aq* sssuajoui • j, + - ;o Siony A\iaAg; 




«" 2 ~ a 

*** -9 a 

• - .2 w 

~ 2 a »> 

u to t- 

>-3 a ja 

<V> 'B 0! >>■ 



a s> 



■snox nt qotq 
a.iunbs jad 'nois 
-aqoQ aiBinpiii 



CO t-I 01 1~; SO t-; OS *- "3 t- -* <36 I-H r-J XS !>; 

•* td iO L-^ M 0> <* 6 O ri ri M M M PI N 
N ?H tH tH tH 



ri??2^ddSSS222rtPN 



,ta>' 



rH>rHOOO 



rH 01 O* r-l l-l CM 



rlNW*iO<Ol> 



^52 ~ _r_r_r_r_r 

"E £. - a "STs" j >>"t S 2 5 3 -3 

5 ^ *cr '> *> ^ ** f-i tc'c? f-i s-i s-i s-j p-i 
(3 -S -S3 £ s -^ — ho .,£ a eg a> s> cp 

Ph — ~! o o .2 2 a, ?>.-£ ."£ £< r£ s ; 

- ~ ~ — — S 3 — ?2 £ jd j3 A .3 fl . 

— - O t) it C. — i — X S3 S- ^ h*. >^~ "^ ^. ► 



'""3 1-3 
S = Sj 

"V- a o <« m 
1 ° o fe a o 

o 3 - a _o ° * 

si i^ ^2 

•^3 ^o a a 
£ d "3 go S 

•o a £ "3 c.,3 
a » « t) -■* 

, o to ~ 

i ^ 5' 



^5 to 

1 £ 3.1 



2 2« 
is 2'a cj 



-5§ - 

.2 tJ " H 



.2 



•iltATJJO 

og'padg 



"I SB 
u93(t;j Sniaq na3 
-ojpiH 'iqSiajM. 



ffl * H "t t-; t-; lO •* U5 ^, 3 M ■*■*■* ' 

co od ad od od oo oo od ooooco t^ t-^ t^ t^ i 



(OC5MNH l *^5 M r^ H K5 ■* « N H 

r-i -+' oq r-i O cb*?3 >d co N d d od w to i 

cjN-*H-/:-fHXOMoi'i | oo?ii 

COMCO'NiM'MHrtH i-IOICMCO 



)l-l OJ OOO CO O OS iH ■" CC '.t CO OC 0-1 O 

n h » q n w i-- m q q x x h n q 

«0 t-^ CO i-i t-^ 1^ r-I OC od VC CO -t 00 3 d 

THr-lrHC^C^CN|COCO'*t01^CCCC010 



O«HOl-t>OH0)iO^inN«XO 
O 'N 00 H Oj ^N CO CI q l> q rH rt X !D 
d ■* 0-i rH CC 0<i CN OC T-H r-I -* i-I O rH C3> 

OXXXNt~W»CH5W^Irtr1 



H=HHc-icHHEHcHHHHE-iE-iHH 

CM CO •<* \G> 



OOOOOOOOOODOOOO 

OO5C0t^®iOTJ<C00<l 



•■}aonij.ioJx^ 
jo -ox 



Hcqco^otot-xoiOHNM-jiioe 



tn '= ^ a o 2 .„ be j= « a 

I * O D. -btj 3 r . tn c$ 

nil %iUl~ 6 

2 - a "2 o ~ =3 2 •= « 5- d 
b _J * .d cs « _ "3 as S o-3 

§rSl^£S>d33oo^ 

si^2^sl-a M ^g 

;o|go|3§E^S,3 



.2 o"S fl B a .= > r- 5 •= a 

xi a a - ^ - - to/a 3 o.2< 
<( p H H trit>i EX'S t< 315 = 



42 ON FOUNDING. 



ON FOUNDING. 

The general object of founding is, to mould iron, 
copper, tin, zinc, lead, &c, &c, in a melted state 
into the various forms required for the parts of 
machines and other constructions. 

Wrought iron and steel cannot be properly melted 
by heat. At high temperatures they drop away and 
spark off, while the main body of the metal main- 
tains its consistency, and it undergoes rapid oxida- 
tion, as is shown by the scales which are perpetually 
formed on its surface. 

These metals are, however, in this condition ren- 
dered extremely ductile, and the wrought iron espe- 
cially may be fashioned with facility into any 
required form, by the application of the hammer. 
On the contrary, pig iron, of which wrought iron 
and steel are preparations, has peculiarly the pro- 
perty of liquefaction by heat, and is therefore well 
adapted as a material for castings, in which strength 
and hardness are required. 

The business of the founder is therefore to take 
advantage of the common law, according to which 
fluids always find their level. If, for example, a 
quantity of water be poured into a vessel, however 



ON FOUNDING. 43 

curiously shaped, it first finds the bottom, and then 
spreads on all sides as it rises, filling every corner 
it can reach. The body of water must then be a 
perfect model in form of the interior of the vessel, 
and this may be seen by solidifying it in its place 
by the application of cold, and extracting the body 
of ice. 

To mould a quantity of melted metal into a 
desired form, two things are therefore necessary : 
first, a model, or pattern of the required form. 
Secondly, a substance of sufficient susceptibility and 
adhesiveness to receive accurately, and to retain 
impressions of that pattern made upon it, against 
the violence of the liquid metal, when run into the 
mould which is thereby formed. 



ON BRASS FOUNDING. 

Brass founding, considered as a branch of engi- 
neering, is beset with a host of empirical rules and 
fancies, to an extent which natur.ally surprises the 
scientific practician, when he considers it with regard 
to the present calculating and philosophizing age. 



44 ON BRASS FOUNDING. 

Every founder thinks lie possesses the only true 
and orthodox system of producing first-rate castings, 
and, as a matter of course, every one differs from 
his neighbour in his routine of practice, without 
reflecting that the process admits as fully of a reduc- 
tion to scientific rules as any of its sister branches 
of the manipulatory art. 

It is scarcely necessary to observe, that excellence 
can never be attained in any art in the prosecution 
of which so loose a system is tolerated : guess-work 
will ever give chance results, productive only of 
inconveniences and objections, which a more system- 
atic code of regulations would entirely obviate. The 
number of alloys of copper which come under the 
generic name of brass, as has been shown, amount 
to a numerous family, and are of the greatest im- 
portance, not only to the engineer, but to artists 
generally, involving the use of the following differ- 
ent metals, all of which are required in a greater 
or less degree to suit the variety of operations where 
brass is indispensable : namely, copper, tin, lead, 
zinc, antimony, and, in some cases, nickel. 

The first four of these metals are those in the 
greatest request for engineering purposes. The 
leading metal of this series, copper, was known to 
the ancients previous to the discovery of malleable 



ON COPPER. 45 

iron, and was applied to all the purposes for which 
the latter metal alone is now used. 

Although we find brass frequently spoken of in 
the Scriptures, as well as in many portions of pro- 
fane history, yet it is a well ascertained fact that 
this refers to copper ; the brass of the present day 
being a discovery of much later date. 



COPPER. 



The word copper is derived from the Island of 
Cyprus, where it was first wrought by the Greeks. 
The best method of obtaining it pure, where extreme 
purity is an object of importance, is to dissolve it 
in nitric acid : the solution is then diluted, and a 
piece of iron introduced, upon which the pure metal 
is precipitated, any adherent particles of iron being 
readily removed by washing with dilute sulphuric 
acid. Another method has lately been discovered 
of purifying copper, namely, by melting 100 parts 
of it, with 10 parts of copper scales (black oxide), 
along with 10 parts of ground bottle-glass, or other 
flux. Mr. Lewis Thompson, who received a gold 



46 ON THE REDUCTION OF COPPER. 

medal from the Society of Arts, for this invention, 
says that, after the copper has been kept in fusion 
for half an hour, it will be found at the bottom of 
the crucible, perfectly pure, while the iron, lead, 
arsenic, &c, &c, with which this metal is usually 
contaminated, will be oxidized by the scales, and 
will dissolve in the flux, or be volatilized. Thus he 
has obtained perfectly pure copper from brass, bell- 
metal, gun-metal, and several other alloys, contain- 
ing from 4 up to 50 per cent, of iron, lead, bismuth, 
antimony, arsenic, &e. The scales of copper are 
cheap, being the product of every large manufac- 
tory. Copper melts at a white heat, and by slow 
cooling may be crystallized. Its specific gravity is 
9, nearly. It melts at a temperature of 1996° 
Eahr. 



On the Reduction of Copper. 

The reduction of copper ore is made by several 
consecutive processes. The first is by calcining it, 
and, when the ore is sufficiently " roasted" to oxi- 
date the iron which it contains, it is melted. The 
melted metal is, after a time, suffered to flow into a 
pit filled with water, by which it becomes granu- 
lated. 



ON TIN. 47 

It then undergoes further heating, and "what is 
called technically its slag (or scoria) is taken off, and 
it is allowed again to run off into water. 

After these processes it is cast in sand, when it 
becomes solid, and in this state is called "blistered 
copper." 

It is now fit for what is called the refinery, and 
undergoes an operation called refining, or toughen- 
ing. This is considered to be an operation of deli- 
cacy, and requires great skill and care in the work- 
men. It is conducted to a furnace similar to the 
melting furnace, and the object is to thoroughly 
purify the metal from any portions of oxygen, which 
is performed by adding charcoal to the copper, while 
it is in fusion, and stirring it occasionally, till it is 
judged to be pure. 



TIN, OR BEDIL IN THE HEBREW. 

The next metal on our list has also been known 
from the remotest ages. It is mentioned by Eleazar 
the priest in the book of Numbers, chapter 81st, 
verse 2 2d. All the other metals supposed to have 



48 ON TIN. 

been then known arc enumerated in the same pas- 
sage. Thus, lexicographers form bedil, " to sepa- 
rate," tin being a separating metal. This carries 
the knowledge and use of tin back 1500 years 
antecedent to the commencement of our era. The 
Phoenicians used tin, of course, m the erection and 
decoration of the Temple of Solomon. Their brass 
was bronze ; zinc had not then been discovered. 
We read of tin, also, having been got by the Cartha- 
ginian navigator, Himiles, from the Scilly Islands ; 
they certainly present appearances of ancient exca- 
vations. Tin occurs, native, in two forms — as per- 
oxide, and as sulphuret of tin and copper. The last 
is rare ; the former constitutes the great source of 
tin, and, in its native mixed state with arsenic, cop- 
per, zinc, and tungsten, is called "tin-stone;" but, 
when occurring in rounded masses, grains, or sand 
in alluvial soil, is called stream tin. The metal 
reduced from the tin-stone forms block tin — that 
from the stream tin forms grain tin. 

The greater part of the East Indian tin comes 
from Siam, Malacca, and Banca. The last place is 
an island near the south-east coast of Sumatra. 
The mines were discovered in 1711 ; in 1T7G there 
were ten pits which were worked by the Chinese on 
account of the King of Talimbang. One hundred 



REDUCTION OF GRAIN AND BLOCK TIN. 49 

and twenty-five pounds cost him only five rix dol- 
lars. The greater part went to Alinia, or was used 
in India. 



On the Reductioyi of Tin, Grain, and Block Tin. 

The best ore of tin is found in Cornwall ; it is 
commonly blasted by gunpowder, and is procured 
in pieces of considerable size, which are stamped, 
by beams shod with iron, to powder. It is then 
well washed, till the earthy particles are carried 
off, and the tin is fit for the smelting-house. 

After being roasted in a reverberatory furnace, 
and again washed, it is a second time subjected to 
the furnace, being now mixed with small coal and, 
in some cases, with a small quantity of lime. The 
melted tin thus produced is at last placed in a small 
furnace, and exposed to a very gentle heat, when 
the purest portion melts first, and is drawn off. This 
is called " common grain tin." And the inferior, 
which still contains a small proportion of copper 
and arsenic, is then cast into pigs, called "block 
tin." 

The purest tin is procured from the stream works 
of Cornwall, and affords from 65 to 75 per cent, of 
the best grain tin ; its specific gravity is about 7.5 ; 



50 OF ZINC. 

it melts at a temperature of 442°. Like copper, it 
is the nucleus of an immense number of subsidiary 
metals, which it is our intention shortly to enter 
upon. 






ZINC. 



Zinc is a metal whose extensive range of appli- 
cation is only now beginning to be understood. It 
is found in the state of oxide and sulphuret ; its 
specific gravity is about 7.7 ; its fusing point is 
773°, but at a temperature of 300°, it becomes 
extremely malleable, and may be rolled into thin 
leaves, or drawn into fine wire. One of its most 
valuable modern applications, is as a protective 
covering for iron, being the best known substance 
for this purpose. The purifying of zinc may be 
eifected by melting the impure metal with lead, in 
equal parts, in a deep iron pot, stirring them well 
together, skimming off the impurities as they rise, 
covering the surface with charcoal to prevent oxi- 
dation, and keeping them in a fused state for three 
hours. The lead descends to the bottom by its 
greater density, and leaves the zinc above, to be 



ON LEAD. 51 

drawn off by a pipe in the side of the melting-pot. 
This contrivance is the subject of a patent, granted 
to Mr. William Godfrey Kneller, in 1844. 



LEAD. 



Lead was also known to the ancients. Its specific 
gravity is 11.4 ; melts at a temperature of 612°. 
This metal is highly poisonous, and the greatest 
amount of caution ought to be observed in its appli- 
cation to domestic purposes, as, when in contact 
with water in open vessels, it quickly tarnishes, and 
small crystalline scales of oxide of lead are formed, 
a portion of which dissolves in the water, and is 
again precipitated in the form of a carbonate. If, 
however, the water contains a very slight amount 
of sulphuric acid, or a soluble sulphate, the corro- 
sion is prevented. 



52 ON ANTIMONY. 



ANTIMONY. 

Antimony was discovered by Basil Valentine (a 
monk), in the fifteenth century. It is of a grayish- 
white, having a slight bluish shade, and very bril- 
liant. Its texture is lamellated, and exhibits plates 
crossing each other in every direction. Its surface 
is covered with herbarizations and foliage. Its spe- 
cific gravity is 6.702. It is sufficiently hard to 
scratch all the soft metals ; it is Very brittle, easily 
broken, and pulverizable. It fuses at 810° Fahr. ; 
it can be volatilized, and burns by a strong heat. 
When perfectly fused and suffered to cool gradually, 
it crystallizes in octahedra. It unites with sulphur 
and phosphorus. It decomposes water strongly. It 
is soluble in alkaline sulphates; sulphuric acid 
boiled upon antimony, is feebly decomposed. Nitric 
acid dissolves it in the cold ; muriatic acid scarcely 
acts upon it. The oxygenated muriatic gas inflames 
it, and the liquid acid dissolves it with facility. 
Arsenic acid dissolves it by heat with difficulty. It 
unites by fusion with gold, and renders it pale and 
brittle. Platina, silver, lead, bismuth, nickel, cop- 
per, arsenic, iron, cobalt, tin, and zinc unite with 



ORDER AND WORKING OF METALS. 53 

antimony by fusion, and form with it compounds 
more or less brittle. Mercury does not alloy with 
it easily. We are little acquainted with the action 
of alkalies upon it. Nitrate of potash is decomposed 
by it. It fulminates by percussion with oxygenated 
muriate of potash. 



The order and facility of working these metals 
vary considerably with the purpose to which they 
are applied. Thus, regarding their wire-drawing 
ductibility, gold is the most ductile metal, being 1. 
The four first metals are as follows : copper 5, zinc 
6, tin 7, lead 8. Their relative values as laminable 
substances are considerably different : thus, under 
the same circumstances, copper is 3, tin 4, lead 6, 
zinc 7. 

The following tabulated statements exhibit the 
most approved properties of the most useful class 
of alloys, as laid down by the best authorities, to- 
gether with the specific purposes to which they are 
adapted. The first we shall treat upon are the 
alloys of copper and tin. In this table the quantity 

of tin is that which is added to one pound of copper. 
5* 



54 



ON COrPER AND TIN. 



COPPER AND TIN. 





1 ounce. 


Soft gun metal. 




li " 
X Z 


A slightly harder alloy, fit for ma- 
thematical instruments. 




li " 


Still harder, fit for wheels. 


11 


to 2 " 


Brass guns. 


2 


to 2J " 


Hard bearings for machinery. 




3 " 


Musical bells. 




H " 


Chinese gongs, cymbals, &c. 




4 " 


Small house bells for domestic pur- 
poses. 




4i « 


Large do. 




5 " 


Largest bells, for churches, &c. 


7 


to 8 " 


Speculum metal for the reflectors 
of telescopes, light-houses, &c. 



Temper, is a mixture of 2 pounds of tin to 1 pound 
of copper, and is used for adding to tin in the 
manufacture of pewter ; the object being to intro- 
duce an extremely small quantity of copper. 



ON BRONZE AND BELL METAL. 55 



BRONZE FOR CANNON, STATUES, ETC. 

Bronze is an alloy of copper, with from 8 to 10 
per cent, of tin, together with small quantities of 
other metals, which are not essential to the com- 
pound. Cannons are cast with an alloy of a similar 
kind, and the ancient bronze statues were of the 
same composition. 



ON BELL METAL. 

Bell metal is a compound of 80 parts copper to 
20 parts tin. The Indian gong, so much celebrated 
for the richness of its tones, contains copper and tin, 
in the above proportions. The proportion of tin in 
bell metal varies, however, from one-third to one- 
fifth of the weight of copper, according to the sound 
required, the size of the bell, and the impulse to be 
given. M. de Arcet has discovered that bell metals 
formed in the proportion of 78 parts copper, united 
with 22 of tin, is indeed nearly as brittle as glass, 
when cast in a thin plate or gong. Yet if it be 



56 ON COPPER AND TIN MIXTURES. 

heated to a cherry-red, and plunged into cold water, 
being held between two plates of iron, that the plate 
may not bend, it becomes malleable. Thus he 
manufactures gongs, cymbals, and tantums out of 
this compound. 



ON COPPER AND TIN MIXTURES. 

The above are the best proportions in use at the 
present day; for some other peculiar objects a 
slightly different mixture is adopted, as a small 
amount of zinc or silver, and even arsenic. The 
best mode of mixing the component metals of this 
alloy, appears to be to melt each separately, and 
then to add the tin to the copper at the lowest stir- 
ring temperature. To complete the combination 
the alloy is again melted very gradually by placing 
the metal in the crucible almost as soon as the fire 
is lighted. The hardness of this alloy, compared 
with the extreme softness of the metals, gives us an 
example of the chemical changes effected by their 
combination. Thus, the speculum metal, as used 
by Lord Rosse, is totally devoid of malleability, and 
from its hardness cannot be acted on by the file. 



SPECULUM, COPPER, AND ZINC. 57 

His speculum consisted of four atoms of chemical 
combining proportions of copper to one of tin : or, 
by weight, 126.4 copper to 58.9 tin. This alloy, 
which is a true chemical compound, is of a brilliant 
white lustre; its specific gravity 8.811; nearly as 
hard as steel, and almost as brittle as sealing-wax. 
The speculum is six feet in diameter, five and a half 
inches thick. It was cast open, ground with emery, 
placed on a table in a cistern filled with water at a 
temperature of 55° Fahr., polished with red oxide 
of iron, procured by precipitation from green vitriol, 
or sulphate of iron, by water of ammonia. 



ALLOYS OF COPPER AND ZINC. 

We now come to the consideration of another 
branch of the copper alloy family of great value in 
the arts. This is copper and zinc. 

The following table contains the best proportions 
of the principal mixtures. In this table the quan- 
tity of zinc is that which is added to one pound of 
copper. 



58 



ALLOYS OF COPPER AND ZINC. 



to | 


tolj 


2 


to 4 


5 


6 



7 to7| 
8 



10* 



14 



16 



ounce. This addition is used principally 
for the purpose of producing 
sound copper castings. 

Gilding metal for jewellers. 

Tombac, or red brass. 

Red sheet brass, pinchbeck, and 
bath metal. 

Purbeck metal. 

Bristol brass. This and the five 
preceding mixtures solder well. 

Good dipping metal. 

The general proportion for all or- 
dinary brass articles. 

Muntz's metal, for ships' fasten- 
ings, sheathing, &c. 

Strong brazing solder, for heavy 
copper work, &c. 

Soft spelter solder. 



From the volatile nature of zinc the above pro- 
portions can seldom be strictly adhered to ; but a 
slight variation does not much affect the filing and 
working of the metal. 

An alloy of copper and lead is often used in place 
of gun metal for inferior work, on account of its 



ON COPPER, ZINC, TIN, AND LEAD. 59 

cheapness and facility of manipulation. It is very 
brittle, particularly where much lead is used. 

The whole of the different metals just discussed, 
when mixed together, constitute gun metal, or brass, 
par excellence. This alloy is applied to a very 
great variety of purposes, and is the one most in 
demand for engineering works. The principal ones 
are compounded as below. 



ALLOYS OE COPPER, ZINC, TIN, AND LEAD. 

1 j ounces tin, J ounce zinc, and 16 ounces copper, 
constitute an extremely tenacious metal, used where 
great strength is required. 

1 J ounces tin, 2 ounces brass, 16 ounces copper, 
for wheels, &c. 

2 ounces tin, 1J ounces brass, 16 ounces copper, 
for articles requiring turning. 

2i ounces tin, 1J ounces brass, 16 ounces copper, 
for bearings, nuts, &c. 

1J ounces tin, 1J ounces zinc, 16 ounces copper, 
a composition for general purposes, used by an emi- 
nent engineer. 



60 ALLOYS. 

2J ounces tin, J- ounce zinc, 16 ounces copper, 
for bearings to resist great strains. 

2J- ounces tin, 2J ounces zinc, 16 ounces copper, 
an extremely hard metal, almost too hard for the 
file. 

1 ounce tin, 2 ounces zinc, 16 ounces copper, good 
button metal. 

5 pounds of zinc to 8 pounds of brass (called pla- 
tina), an extremely pale, nearly white metal, used 
by Birmingham button-makers. 

9 pounds of zinc to 32 pounds of brass, another 
alloy, called Bath metal. 

10 pounds of tin, 6 pounds of copper, 4 pounds 
of brass, constitute white solder. 

14.75 tin, 144 copper, and 12 brass, is the alloy 
of the English standard measure. 

Manheim Gold. — 3 parts copper, 1 part zinc, 
and a small quantity of tin. If these metals 
are pure, and melted in a covered crucible, contain- 
ing charcoal, the alloy bears so close a resemblance 
to gold as to deceive very skilful persons. 

Best Pinchbeck, 5 ounces pure copper, and 1 of 
zinc. 



ALLOYS. 61 

Princess Metal. — 3 parts copper, 1 part common 
brass, and J ounce zinc. 

5J pounds copper, J- pound zinc, best Tombac, 
beautifully red, and is more durable than copper. 

Artificial Gold. — 16 parts virgin platina, 7 parts 
copper, 1 part zinc, put in a crucible, covered with 
powdered charcoal, and melted till the whole forms 
one mass. 

Fine Brazing Solder. — 12 pounds of copper, 11 
pounds of zinc, flux with powdered brimstone. 



We might multiply these examples of the differ- 
ent mixtures, but as we have already extended this 
portion of our article to a considerable length, and 
have given what appear to be the best for general 
purposes, we shall defer any further remarks on the 
subject, until we come to white metals, receipts, &c, 
at the latter part of the work. 
6 



62 REMARKS. 



Having discussed the rationale of the mixture 
and proportion of the metals used in alloys of cop- 
per, the matter leads us to the further consideration 
of casting them. Brass moulding is carried on by 
means of earthen, or sand moulds. The formation 
of sand moulds is by no means so simple an affair 
as it would at first sight appear to be, as it requires 
long practical experience to overcome the disadvan- 
tages attendant upon the material used. The moulds 
must be sufficiently strong to withstand the action 
of the fluid metal perfectly, and, at the same time, 
must be so far pervious to the air as to permit of 
the egress of the gases formed by the action of the 
metal on the sand. If the material were perfectly 
air-tight, then damage would ensue frqm the pres- 
sure arising from the rapidity of the generation of 
the gases, which would spoil the effect of the casting, 
and probably do serious injury to the operator. 

If the gases are locked up within the mould, the 
general result is what moulders term a blown cast- 
ing ; that is, its surface becomes filled with bubbles 
of air, rendering its texture porous and weak, besides 
injuring its appearance. 

Plaster of Paris is often used for a number of the 



FACING. 63 

more fusible metals. This material, however, will 
not answer for the more refractory ones, as the 
heat causes it to crumble away and lose its shape. 

Sand, mixed with clay or loam, possesses advan- 
tages not to be found in gypsum, and is consequently 
used in place of it, for brass and other alloys. In 
the formation of brass moulds, old damp sand is 
principally used in preference to the fresh material, 
being much less adhesive, and allowing the patterns 
to leave the moulds easier and cleaner. 

Meal dust or flour is used for facing the moulds 
of small articles ; but for larger works, powdered 
chalk, wood-ashes, &c, are used, as being more eco- 
nomical. 

If particularly fine work is required, & facing of 
charcoal or rottenstone is applied. Another plan 
for giving a fine surface is to dry the moulds over 
a slow fire of cork shavings, or other carbonaceous 
substance, which deposits a fine thin coating of car- 
bon. This, when good fine facing-sand is not to be 
obtained. 

As regards the proportions of sand and loam used 
in the formation of the moulds, it is to be remarked, 
that the greater the quantity of the former material, 
the more easily will the gases escape, and the less 



64 METALLIC MOULDS. 

likelihood is there of a failure of the casting ; on 
the other hand, if the latter substance predominates, 
the impression of the pattern will be better, but a 
far greater liability of injury to the casting will be 
incurred from the impermeable nature of the mould- 
ing material. This however may be got over with- 
out the slightest risk, by well drying the mould 
prior to casting, as you would have to do were the 
mould entirely of loam. 

For some works, where easily fusible metal is 
used, metallic moulds are adopted. Thus, where 
great quantities of one particular species of casting 
is required, the metallic mould is cheaper, easier of 
management, and possesses the advantage of pro- 
ducing any number of exactly similar copies. The 
simplest example which we can adduce is the cast- 
ing of bullets. These are cast in moulds constructed 
like scissors, or pliers, the jaws or nipping portions 
being each hollowed out hemispherically, so that 
when closed a complete hollow sphere is formed, 
having a small aperture leading into the centre of 
the division line, by which the molten lead is poured 
in. 

Pewter pots, inkstands, printing types, and va- 
rious other articles, composed of the easily fusible 
metals, or their compounds, are moulded on the 



PEWTERING. 65 

same principle. The pewterer generally uses brass 
moulds : they are heated previous to pouring in the 
metal. In order to cause the casting to leave the 
mould easier, as well as to give a finer face to the 
article, the mould is brushed thinly over with red 
ochre and white of an egg ; in some cases, a thin 
film of oil is used instead. 

Many of the moulds for this purpose are extremely 
complex, and, being made in several pieces, they 
require great care in fitting. 

With these peculiar cases we have, at present, 
little to do, and shall conclude with a few observa- 
tions on the method of filling the moulds. The 
experienced find that the proper time for pouring 
the metal is indicated by the wasting of the zinc, 
which gives off a lambent flame from the surface of 
the melted metal. The moment this is observed, 
the crucible is to be removed from the fire, in order 
to avoid incurring a great waste of this volatile sub- 
stance. The metal is then to be immediately poured. 
The best temperature for pouring, is that at which 
it will take the sharpest impression and yet cool 
quickly. If the metal is very hot, and remains long 
in contact with the mould, what is called sand-burn- 
ing takes place, and the face of the casting is in- 
jured. 

6* 



66 COMPLEX OBJECTS. 

The founder, then, must rely on his own judgment, 
as to what is the lowest heat at which good, sharp 
impressions will be produced. As a rule, the smallest 
and thinnest castings must be cast the first in a 
pouring, as the metal cools quickest in such cases, 
while the reverse holds good with regard to larger 
ones. 

Complex objects, when inflammable, are occasion- 
ally moulded in brass, and some other of the fusible 
metals, by an extremely ingenious process ; render- 
ing what otherwise would be a difficult problem a 
comparatively easy matter. 

The mould, which it must be understood is to be 
composed of some inflammable material, is to be 
placed in the sand-flask, and the moulding sand 
filled in gradually until the box is filled up. When 
dry, the whole is placed in an oven sufficiently hot 
to reduce the mould to ashes, which are easily re- 
moved from their hollow, when the metal may be 
poured in. In this way (as will be afterwards shown) 
small animals, birds, or vegetables may be cast with 
the greatest facility. 

The animal is to be placed in the empty moulding- 
box, being held in the exact position required, by 
suitable wires or strings, which may be burnt or 
removed, previous to pouring in the metal. 



ON BELL FOUNDING. 67 

Another mode which appears to be founded on 
the same principle, answers perfectly well when the 
original model is moulded in wax. The model is 
placed in the moulding-box in the manner detailed 
in the last process, having an additional piece of 
wax to represent the runner for the metal. The 
composition here used for moulding is similar to 
that employed by statue founders in forming the 
cores for statues, busts, &c, namely, two parts 
brick-dust to one of plaster of Paris. This is mixed 
with water and poured in so as to surround the 
model well. The whole is then slowly dried, and 
when the mould is sufficiently hardened to withstand 
the effects of the molten wax, it is warmed, in order 
to liquify and pour it out. When clear of the wax, 
the mould is dried and buried in sand, in order to 
sustain it against the action of the fluid metal. 

If our limits permitted, we might mention the de- 
tails of numerous other works in the founding of 
brass. We must for the present content ourselves 
with a brief examination of one or two cases which 
come more or less within the province of the engi- 
neer. One of these is the founding of bells, a sub- 
ject of considerable interest, as works of this kind 
are often of very considerable magnitude, and de- 
mand the skilful attention of the engineer. Large 



68 ON GUN FOUNDING. 

bells are usually cast in loam moulds, being swept 
up, according to the founder's phraseology, by 
means of wooden or metal patterns, 'whose contour 
is an exact representation of the inner and outer 
surfaces of the intended bell. Sometimes, indeed, 
the whole exterior of the bell is moulded in wax, 
which serves as a model to form the impression in 
the sand, the wax being melted out previous to 
pouring in the metal. This plan is rarely pursued, 
and is only feasible when the casting is small. 

The inscriptions, ornaments, scrolls, &c, usually 
found on bells, are put on the clay mould separately, 
being moulded in wax or clay, and stuck on while 
soft. The same plan is pursued with regard to the 
ears, or supporting lugs, by which the bell is hung. 



BRASS GUNS 



Are another important branch of this manufac- 
ture. They are moulded in a manner quite distinct 
from any other work of this nature. The exterior 
surface of the gun is produced by wrapping gaskin 
or soft rope round a tapered rod, of a length slightly 



ON GUN FOUNDING. 69 

greater than that of the gun. Upon this foundation 
of rope the moulding loam is then applied ; the 
surface being turned to the exact shape and propor- 
tions of the gun. 

A long fire is used by the founder in this process, 
in order to dry the mould as he proceeds in its 
manufacture. When perfectly dry, the surface of 
the mould is black-washed over, and again covered 
■with loam to a depth of two or three inches. This 
exterior coat of loam is secured and strengthened 
by a number of iron bands, and the whole is well 
dried. The primary mould is now completely with- 
drawn from the outer shell, the formation of which 
renders it an easy matter, as the timber rod leaves 
the rope with great facility, when the latter may 
be withdrawn, and the clay covering picked out 
afterwards. 

The trunnions of the gun are formed separately, 
and attached to the shell in the ordinary way. 
When finished, the moulds are sunk perpendicu- 
larly in a sand pit, near a reverberatory furnace, a 
vertical runner being made, leading to each mould, 
which it enters near the bottom. A suitable chan- 
nel communicates with the furnace containing the 
brass intended for the guns. The metal being in- 



70 ON FIGURE CASTING. 

troduced at the bottom of the mould, no air can 
possibly be detained by its entrance, as each mould 
is full open to the atmosphere at the top. 



FIGURE CASTING 

Is another branch of our subject, and one which, 
from its general complexity, ranks as the greatest 
effort of the founder. As an example of this pro- 
cess we shall take the moulding of thin ornaments 
in relief. 

The ornament, whatever it may be, a monumental 
bas-relief for instance, is first modelled in relief, in 
clay or wax, upon a flat surface. A sand flask is 
then placed upon the board, over the model, and 
well rammed with sand, which thus takes the im- 
press of the model on its lower surface. A second 
flask is now laid on the sunken impression, and also 
filled with sand, in order to take the relief impres- 
sion from it. This is generally termed the cope, or 
back mould. The thickness of the intended cast is 
then determined by placing an edging of clay round 
the lower flask, upon which edging the upper one 
rests, thus keeping the two surfaces at the precise 



ON FIGURE CASTING. 71 

distance from each other, that it is intended the 
thickness of the casting shall be. 

In this process, the metal is economised to the 
greatest possible extent, as the interior surface, or 
back of the casting, is an exact representation of 
the relief of the subject ; and the whole is thus made 
as thin in every part as the strength of the metal 
permits. 

Several modifications of the process just described 
are also made use of, to suit the particular circum- 
stances of the case. What we have said, however, 
is a detail of the principle pursued in all matters of 
a similar nature. In conclusion we will give a com- 
position for cores that may be required for difficult 
jobs, where it would be extremely expensive to make 
a core-box for the same : — 

Make a pattern (of any material that will stand 
moulding from) like unto the core required. Take 
a mould from the same in the sand, in the ordinary 
way ; place strengthening wires from point to point, 
centrally ; gate and close your flask. Then make a 
composition of two parts brick-dust and one part 
plaster of Paris ; mix with water and cast. Take it 
out when set, dry it, and place it in your mould 
warm, so that there may be no cold air in it. 



72 BRASS MIRRORS, ETC. 



BRASS MIRRORS.* 

An Etruscan mirror, placed in the hands of 
" Gerharht of Berlin," was found to consist, in 100 
parts, of 67.12 copper, 24.93 tin, 8.13 lead ; ap- 
proximating closely to an alloy of 8 parts copper, 
3 of tin, and 1 of lead. The oxide of tin obtained 
in the course of analysis was carefully examined 
before the blow-pipe for antimony, but he saw no 
trace of that metal. 

A similar mirror has been analysed by " Klap- 
roth." He found 62 per cent, copper, 32 tin, and 
6 per cent. lead. 



Copper. — Copper is thick and pasty, and without 
some alloy will not run into the cavities and sinu- 
osities of the mould. 

Metals, — A quarter of a grain of lead will render 
an ounce of gold perfectly brittle, although neither 
gold or lead are brittle metals. 

* See Job, xxxvii. 18; Exodus, xxxviii. 8. 



SURFACE OF METALS, ETC. 73 

Surface of Metals. — The surface of metals should 
be carefully defended, while in the fluid state, from 
the action of the atmosphere, by a stratum of wax, 
pitch, or resin, if the fusing point be low ; or by a 
layer of salt, powdered glass, borax, charcoal, &c., 
if it is high. 

Blanched Copper. — 8 ounces of copper, and J an 
ounce of neutral arsenical salt, fused together under 
a flux of calcined borax and pounded glass, to which 
charcoal powder is added, makes blanched copper. 

British Weapons and Tools in Bronze, anciently 
called Corinthian and Syracuse Brass. — The metal 
of which the British weapons and tools were made, 
has been chemically analysed in modern times, and 
the proportions appear to be — 

In a spear head, 1 part of tin to 6 parts of copper. 
In an axe head, 1 do. 10 do. 

In a knife, 1 do. 7J do. 



74 ON BRASS. 



ON BRASS. 

In Germany brass appears to have been made 
for centuries before the manufacture was introduced 
into England. This is stated to have been done by 
a German, who worked at Esher, in Surrey, in the 
year 1649. The analysis of a few pieces of bronze, 
of undoubted antiquity, namely, a helmet with an 
inscription (found at Delphi, and now in the British 
Museum), some nails from the treasury of Atreus, 
at Mycenae, an ancient Corinthian coin, and a por- 
tion of a breast-plate, or cuirass, of exquisite work- 
manship (also in the British Museum), affords about 
87 to 88 parts copper to about 12 to 13 tin, per 
cent. 

The experiments of Klaproth and others give 
nearly the same results as to ingredients ; the quan- 
tities sometimes slightly differ. Lead is contained 
in some specimens, as has been shown. Zinc, and 
the nature of it, as heretofore observed, was not 
known to the ancients. 

In an antique sword, found many years ago, in 



CASTING IN PLASTER. 75 

France, the proportions in 100 parts were, 87.47 
copper, 12.53 tin, with a small portion of lead, not 
worth noticing. 



METHOD OF CASTING IN PLASTER — MEDALLIONS, ETC. 

Obtain some fine plaster, of good colour, and 
pass it through a muslin sieve, to remove any coarser 
particles which may be present. By mixing gum 
arable with the water intended to he used in the 
plaster, not only will the plaster be rendered very 
hard when it sets, but a beautiful gloss will be given 
to the surface. Care must be taken to drop the 
plaster powder gradually into the water, and to per- 
mit the bubbles to rise before the mixture is stirred ; 
otherwise it will become lumpy. The plaster should 
be of the consistence of the yolk of an egg, and, of 
course, used immediately. If the medal intended 
to be copied is a valuable one, with a smooth surface, 
it will be advisable not to oil it, as, in cleaning the 
oil off, the polish may be injured; but if the 
surface be rough there will be no remedy, and the 
oil must afterwards be removed, by dabbing the sur- 
face of the medal gently with a soft cloth. 



76 CASTING IN PLASTER. 

A rim of thin lead, brass, copper, or even oiled 
paper, is then tied round the medal, and some liquid 
plaster, in the first place, stippled over its surface 
with a soft brush, to prevent the formation of air 
bubbles, as well as to insure its insertion into the 
most minute crevices; after which the plaster is 
poured upon the surface to the thickness of half an 
inch, or an inch if a large medal. 

To separate the mould from the medal, all we 
have to do is to immerse it in water, when it is 
readily removed ; otherwise the mould is sure to be 
broken. 

To obtain a plaster cast from this mould, we must 
oil it with warm boiled linseed oil, and allow it seve- 
ral days to dry. Whenever the mould is used it 
must be well oiled; otherwise the surface of the 
casting will be destroyed. The best olive oil must 
be used, or the colour of the plaster will be injured. 



TRANSFERRING AND VARNISHING. 77 



TO TRANSFER ENGRAVINGS TO PLASTER CASTS. 

Cover the plate with ink, and polish its surface 
in the usual way ; then put your rim round it, as 
before stated, and pour in your plaster, mixed as 
before. Jerk the plate repeatedly, to allow the 
air bubbles to fly upwards, and let it stand one hour ; 
then take the cast off the plate, and a very perfect 
impression will be the result. 



TO VARNISH PLASTER CASTS. 

Plaster casts are varnished by a mixture of soap 
and white wax in boiling water. A quarter of an 
ounce of soap is dissolved in a pint of water, and 
an equal quantity of wax afterwards incorporated. 
The cast is dipped in this liquid, and, after drying 
a week, is polished, by rubbing with soft linen, pro- 
ducing a polish like marble. If to be exposed to 

the weather, saturate them with linseed oil mixed 

7 * 



78 CONCAVE AND CONVEX MOULDS. 

with wax, or rosin may be combined. In casting 
the plaster, always use spring water and gum 
arabic. 



TO CAST CONCAVE OR CONVEX MOULDS OF MEDALS, 
ON "TIN-EOIL," WITH PLASTER. 

Take a medal, &c, and cover it with very thin 
" tin-foil," which press as close to the medal as you 
can ; go over every part with a brush, laying on 
tolerably hard, in order to press the tin-foil into 
every cavity of the medal. After which, you may 
pour plaster upon it, and, when it is hard, take the 
medal out, leaving the tin-foil in the plaster ; then, 
with a little fine olive oil, anoint the tin-foil, and 
the plaster where it must part, and pour more plas- 
ter upon the tin-foil, which also let harden. You 
may then separate them, and take out the tin-foil, 
and you will have both a concave and a convex 
mould. 



CASTING COMPLEX OBJECTS. 79 



TO CAST VEGETABLES, INSECTS, SMALL BIRDS, FROGS, 
EISH, ETC., IN PLASTER MOULDS. 

Provide a trough of boards, nailed together so 
as not to let the water run through the joints. Sus- 
pend in the trough, by thread or Holland twine, 
in several places, the vegetable, plant, insect, &c, 
which you would cast, which being performed, mix 
four parts of plaster of Paris, and two parts of fine 
brick-dust, with common water, to the consistence 
of cream, and with this cover the thing intended to 
be cast, observing not to distort it, by any means, 
from its natural position. When you have filled 
your trough, let it harden by placing it near the fire 
by degrees till you can make it red hot. Then let 
it cool, and, with a pair of bellows, blow and shake 
as much of the ashes out of the mould as you can. 
You must now put a small quantity of quicksilver 
into the mould, and shake it, in order to loosen 
every part of the ashes therein ; also to make a 
passage through where the strings were tied, in 
order to let the air out when you pour in your 
metal. 



80 FUSIBLE METALS. 



TO PREPARE A METAL FOR THE ABOVE WORK. 

Take of grain tin 6 ounces, bismuth 2 ounces, 
and lead 3 ounces. Melt them together in an iron 
ladle, and you may cast in the above mould to your 
satisfaction. 

You may combine the above ingredients in such 
proportions as to compose a metal that will melt in 
boiling water. Thus, 

Sir Isaac Newton s Fusible Metal is composed of 
8 parts bismuth, 5 parts lead, and 3 parts tin. This 
alloy melts at 212°. 

Hose's Alloy is still more fusible : it is 2 parts 
bismuth, 1 lead, and 1 tin, and melts at 201°. 

The late Dr. Daltons Fusible Alloy. — 3 parts 
tin, 5 parts lead, and 10J parts bismuth ; melts at 
197°. The addition of a little mercury makes it 
more fusible, and fits it to be used as a coating to 
the insides of glass globes. 



CASTING IN WAX. 81 

An alloy of equal parts of tin and bismuth melts 
at 280°. A less proportion of bismuth adds to the 
hardness of tin, and hence its use in the formation 
of pewter, or pewter solder. 



TO CAST IN WAX. 

The mould is first made in plaster, but before 
being used it is placed in warm water, of which it is 
allowed to absorb as much as it will take — oil not 
being used in this process. The surface must then 
be allowed to dry, or the wax would not adhere 
closely. Pure wax is too greasy for the purpose, 
and bladder flake-ivhite is therefore mixed with it ; 
the quantity cannot be stated ; but the addition of 
too much gives wax the appearance of plaster, by 
taking away its richness. The oftener the wax is 
remelted, the more its colour is injured. 

In order to obtain a gray marble colour, a marble 
powder, procurable at any statuary, is mixed with 
the wax, which not only gives a beautiful appearance 
to it, but renders it more durable. 

The wax is poured into the mould and allowed to 



62 ' CASTING IN SULPHUR. 

flow over its surface, and by moistening the plaster 
mould in water when the wax has become hard, the 
cast is easily removed. Wax models may be fastened 
by means of linseed oil and flake-white, and also by 
a combination of bees' wax and resin. 



TO CAST IN SULPHUR. 

This is a very permanent mode, but as a mould 
it can only be used for plaster ; for hot wax or sul- 
phur would injure its surface. When sulphur is 
heated to the temperature suitable for forming casts, 
it becomes nearly black, and has, therefore, to be 
coloured in the proportion of one ounce of Vermil- 
lion to three ounces of sulphur. The surface of the 
mould, however, need only be coated with this 
expensive mixture, and common sulphur in any 
quantity. 

You must use wood to stir the sulphur, as iron 
will take away its colour. The sulphur will take 
fire in melting, unless it is properly stirred, and at 
first will become thick and viscid, but by continuing 
the application of heat, it will again assume a per- 
fectly liquid form. 



CASTING IN GLUE. 83 



TO CAST IN GLUE. 

If a medal is so much sunk and engraved that 
you cannot get a plaster cast off, a mould may be 
obtained by pouring glue upon it. In this manner 
a bunch of grapes can be taken in the natural state, 
and by cutting the glue down the centre, the grapes 
can be extracted, and the mould used to produce a 
representation of the original in plaster. Isinglass 
may be similarly used, but it is first mixed with 
flake-white, in the state of powder. When the 
plaster is hard, place the whole in boiling water, 
when the glue will melt away, leaving a perfect cast 
of plaster grapes. 



TO MAKE A FINE GLUE, WHEREWITH YOU MAY CAST 
CURIOUS MEDALS. 

Steep isinglass in brandy, and when it is dis- 
solved boil it together with water, and pour it over 
any medal, and when dry it will appear perfect. It 



84 CASTING IN BREAD PASTE. 

must be of a tolerably thick consistence, much like 
common glue. 



TO CAST IN BREAD PASTE. 

Take the inside of fresh bread, and work it up 
well with vermillion — the longer the better, until it 
becomes viscid and tough. It is then to be worked 
well into the mould. After having obtained the 
mould, it must be fastened down upon a piece of 
wood, by wetting it so as to prevent it from warp- 
ing as it dries. After it has been thoroughly dried 
you may oil it, and then obtain as many casts as 
you please from it, in plaster, wax, or sulphur. 

By means of bread-paste a traveller may always 
take a model of any small object of interest he 
meets with on his journey; and thus a proper 
knowledge of its mode of use becomes invaluable. 
Scrolls, ruins of tombs and temples, &c, have often 
thus been copied and brought home at a trifling cost. 



CASTING IN ISINGLASS AND RICE GLUE. 85 



TO CAST FIGURES IN IMITATION OF IVORY. 

Make isinglass and strong brandy into a paste 
with powder of egg-shells, well ground. You may 
make it whatever colour you please, but cast warm 
water into your mould, which should be previously 
well oiled over. Leave the figure in the mould to 
dry; and on taking it out it will be found to bear a 
strong resemblance to ivory. 



RICE GLUE STATUARY. 

Mix rice flour intimately with cold water, and 
gently simmer it over the fire, when it readily forms 
a delicate and durable cement, not only answering 
the purpose of common paste, but admirably adapted 
to join together paper, card, &c. When made of 
the consistence of plastic clay, models, busts, basso- 
relievos, &c, may be formed ; and the articles when 
dry are very like white marble, and will take a high 
polish, being very durable. In this manner the 
8 



86 COMPOSITION FOR ORNAMENTS. 

Chinese and Japanese make many of their domestic 
idols. Any colouring matter may be used at plea- 
sure. 



A COMPOSITION FOR ORNAMENTS. 

Take pounded chalk, what quantity you please, 
acid thereto as much thin glue as will make it into 
paste, which mix well together. Then put it into 
moulds, being a little oiled, and press it well in ; 
after which take it out, and it will grow as hard as 
stone. 

You must make no more of it than you want for 
present use ; if left it grows hard, and cannot be 
used again, 



ON ALLOYS AND AMALGAMS. 87 



ALLOYS, AMALGAMS, ETC. 

The formation of alloys appears to depend upon 
the chemical affinity of the metals for each other, 
and in some instances it seems to he wanting, for no 
combination occurs. Thus, according to Gellert, 
bismuth and zinc do not combine. 

The change of properties which metals undergo 
by combining, furnishes strong evidence of its aris- 
ing from chemical affinity and action. Thus, with 
respect to colour, copper, a reddish-coloured metal, 
by union with zinc, which is a white one, gives the 
well known "yellow alloy brass." 

The fusing point of a mixed metal, is never the 
mean of the temperature at which its constituents 
melt, and it is generally lower than that of the most 
fusible metal of the alloy. 

Alloy is a word used to designate either a natural 
or artificial compound of two or more metals ; ex- 
cept when mercury is one of them ; the mixture is 
then termed an amalgam,. 

The natural alloys are far less important sub- 
stances than those which are artificially procured. 
Thus arsenic occurs combined with the following 



88 NATIVE ALLOYS, ETC. 

metals, namely, antimony, bismuth, cobalt, iron, 
nickel, and silver. 

There is also found a native alloy of antimony 
and nickel, and of antimony, cobalt, and nickel ; 
others might be mentioned ; but there is no instance 
of a native alloy, strictly speaking, being applied to 
any useful purpose. Whereas, the artificial alloys, 
as has been fully shown, are of the highest import- 
ance, both for the uses of common life, and for manu- 
facturing purposes. By uniting different metals, 
compounds are formed, which possess a combination 
of qualities not occurring in any one metal. 

Platina is always used in a pure state, and cop- 
per, iron, lead, and zinc, are also very commonly so 
used. But gold, silver, tin, antimony, and bismuth, 
are, as we have shown, generally alloyed ; the first 
three on account of their softness, and the two latter 
because they are extremely brittle. Gold and silver 
are hardened by alloying with copper; copper is 
hardened by zinc, tin, &c, &c. 

All alloys formed of brittle metals are brittle ; 
those made of ductile metals are in some cases duc- 
tile and in others brittle. When the proportions 
are nearly equal, there are as many alloys which 
are brittle as ductile — but when any of the metals 
is in excess they are most commonly ductile. In 



DENSITY OF METALS. 



89 



combining ductile and brittle metals, the compounds 
are brittle if the brittle metal exceed, or nearly 
equal the proportion of the ductile one ; but when 
the ductile metal greatly exceeds the brittle one, 
the alloys are usually ductile. 

The density of alloys sometimes exceeds, and in 
other cases is less than that which would result from 
calculation. The following alloys afford examples 
of " increased and diminished density:" — 



Increased Density. 

Gold and Zinc. 
Gold and Tin. 
Gold and Bismuth. 
Gold and Antimony. 
Gold and Cobalt. 
Silver and Tin. 
Silver and Bismuth. 
Silver and Antimony. 
Silver and Zinc. 
Silver and Lead. 
Copper and Zinc. 
Copper and Tin. 
Copper and Palladium. 
8* 



Diminished Density. 
Gold and Silver. 
Gold and Iron. 
Gold and Lead. 
Gold and Copper. 
Gold and Iridium. 
Gold and Nickel. 
Silver and Copper. 
Iron and Bismuth. 
Iron and Antimony. 
Iron and Lead. 
Tin and Lead. 
Tin and Palladium. 
Tin and Antimony. 



90 BRONZE, BELL, AND SPECULUM METALS. 

Increased Density. Diminished Density. 

Copper and Bismuth. Nickel and Arsenic. 
Copper and Antimony. Zinc and Antimony. 
Lead and Bismuth. 
Lead and Antimony. 
Platina and Molybdenum. 
Palladium and Bismuth. 

Not only are the properties of metals altered by 
combination, but different proportions of the same 
metals produce very different alloys. Thus, by 
combining 90 parts of cOpper with 10 parts of tin, an 
alloy is obtained of greater density than the mean 
of the metals ; and it is also harder and more fusible 
than the copper; it is slightly malleable when slowly 
cooled ; but, on the contrary, when heated to red- 
ness and plunged into cold water, it is very malle- 
able. This compound is known by the name of 
bronze. 

Again, as has been previously laid down, if 80 
parts of copper be combined with 20 parts of tin, 
the compound is the extremely sonorous one, called 
bell metal. 

An alloy consisting of two-thirds copper, and 
one-third tin, is susceptible of a very fine polish, 
and is used as speculum metal. 



COMBINATION AND CHEMICAL ACTION. 91 

It is curious to observe in these alloys, that in 
bronze, the density and hardness of the denser and 
harder metal are increased, by combining with a 
lighter and softer one ; while, as might be expected, 
the fusibility of the more refractory metal is in- 
creased by uniting with a more fusible metal. In 
bell metal, the copper becomes more sonorous by 
combination with a metal which is less so. These 
changes are clear indications of chemical action. 

It has been already observed that the natural 
alloys, considered as such, are not important bodies. 
The only one, if indeed that may be reckoned so, 
is the alloy of iron and nickel, constituting meteoric 
iron, and of which the knives of the Esquimaux 
appear to be made. 

The artificial metallic alloys are of the highest 
degree of utility. Thus, gold is too soft a metal to 
be used either for the purposes of coin or ornament ; 
it is therefore alloyed with copper. Silver, though 
harder than gold, would also wear too quickly unless 
mixed with copper ; and copper is improved both in 
hardness and colour by combination with zinc and 
tin, forming brass and bronze. 



92 



TABLE OF YELLOW BRASS. 



YELLOW BRASS. 

The following table exhibits the composition of 
several varieties of this species of brass. No. 1 is 
a cast brass, of uncertain origin. No. 2 is the brass 
of Jemappes. No. 3 is the sheet-brass of Stolberg, 
near Aix-la-Chapelle. No. 4 and 5, the brass for 
gilding, according to De Arcet. No. 6, the sheet- 
brass of Romilly. No. 7, English brass- wire. No. 
8, Augsburg brass-wire. No. 9, the brass-wire of 
Neustadt, Eberswald, in the neighbourhood of 
Berlin. 



Metal. 


No.l. 


No. 2. 


No. 3. 


No. 4. 


No.5. 


No. 6. 


No. 7. 


No. 8. 


No. 9. 


Copper . 
Zinc. . . 
Lead . . 
Tin . . . 


01.6 

35.3 

2.9 

0.2 


6-1.6 

33.7 

1.4 

0.2 


64.8 

32.8 
2.0 
0.4 


63.70 

35.55 

0.25 

0.50 


64.45 

3244 

2.86 

0.25 


70.1 
29.9 


7<i.-- ,; .i 

29.-26 

0.28 

0.17 


71.89 

27.63 

0.8,5 


70.16 

27.45 

0.20 

0.79 




100.0 


100.0 


100.0 


100.0 


100.0 


loo.o 


100.0 


100.0 


100.0 
nearly 



COPPER MEDALS AND MEDALLIONS. 93 



TO MAKE COPPER MEDALS AND MEDALLIONS. 

Let black oxide of copper, in a fine powder, be 
reduced to the metallic state, by exposing it to a 
stream of hydrogen in a gun-barrel heated barely 
to redness. The metallic powder thus obtained is 
to be sifted through crape upon the surface of the 
mould, to the thickness of a quarter or half an inch, 
and is then to be strongly pressed upon it, first by 
the hand, and lastly by percussion with a hammer. 
The impression thus formed is beautiful, but it -ac- 
quires much more solidity by exposure to a red heat, 
out of contact with the air. Such medals are said 
to have more tenacity than melted copper, and to 
be sharply defined. This plan was discovered by 
M. Boettger, for which he was awarded the gold 
medal of the Society of Arts. 

An improvement on the above plan, whereby you 
may prepare the powder of copper more easily and of 
better quality, by precipitating a boiling hot solution 
of sulphate of copper, with pieces of zinc ; boiling 
the metallic powder, thus obtained, with dilute sul- 
phuric acid, for a little, to remove all traces of the 



94 CHEMICAL AFFINITY AND AMALGAMS. 

zinc or oxide ; washing it next with water, and dry- 
ing it in a tubulated retort by the heat of a water- 
bath, while a stream of hydrogen is passed over it. 
This cupreus precipitate possesses so energetic an 
affinity for oxygen, that it is difficult to prevent it 
passing into the state of orange oxide. 



AMALGAM. 

Amalgam, a compound of two or more metals, of 
which one is always mercury ; and this circumstance 
distinguishes an amalgam from an alloy. Nature 
presents us with only one amalgam, which is silver, 
and is termed by mineralogists "native amalgam." 
It occurs in Hungary, Sweden, &c, and is met with 
either semi-fluid, massive, or crystallized in rhombic 
dodecahedrons. Klaproth found it to consist of 64 
parts of mercury, and 30 of silver, out of 100 parts. 
Most metals may be amalgamated with mercury, 
and the combination appears to depend on chemical 
affinity. 

When the cohesion of a metal is slight, as in the 
cases of potassium and sodium ; or when its affinity 
for mercury is considerable, as in the instances of 



AMALGAMATION OF METALS. 95 

gold and silver, amalgamation takes place readily, 
by mere contact. When, on the other hand, the 
cohesion of a metal is strong or its affinity for mer- 
cury is weak, heat or intermediate action, or both, 
are requisite to effect amalgamation. 

If forty-four parts of mercury be mixed with one 
part of potassium, combination occurs with the evo- 
lution of much heat ; and when the resulting amal- 
gam is cold, it is hard and has the appearance of 
silver. When the quantity of mercury exceeds one 
hundred parts to one of potassium, the compound is 
liquid, and an amalgamation containing only 1.5 
per cent, of potassium is susceptible of crystalliza- 
tion. The density of an amalgam exceeds that of 
the mean of the metals ; this and the tendency of 
one or both metals to oxidize, are additional indica- 
tions of chemical combination. 

There are some metals, it has been observed, re- 
quiring heat to amalgamate them. Antimony offers 
an example of this : to effect combination it must be 
melted, and while liquid mixed with hot mercury. 
Mere heat, however, causes scarcely any action be- 
tween iron and mercury ; they may be amalgamated 
by mixing the filings of the metal with powdered 
alum, and rubbing them together in a mortar with 
a little water. After trituration, the alum may be 



90 AMALGAMATION OF METALS. 

washed out. By the intervention of tin or zinc, 
iron may be combined with mercury, and a double 
amalgam is formed. Platina also unites with mer- 
cury, by the intervention of the amalgam of potas- 
sium, but not by direct action. The double amalgam 
of iron and zinc does not rapidly undergo any 
change, and is not attracted by the magnet. All 
amalgams are decomposed by a red heat ; the mer- 
cury being distilled, and the more fixed metal re- 
maining. The process of amalgamation and decom- 
position is employed to separate gold and silver from 
their ores. The mercury obtained by decomposing 
the amalgams is distilled and repeatedly used for 
the same purpose, with comparatively little loss. 

The amalgams of gold and silver are used or em- 
ployed in the process of gilding and plating. We 
have also shown the amalgam of tin is largely used 
in what is called silvering mirrors, and that various 
amalgams of tin and zinc are employed for exciting 
electricity in the machine. 



ON BISMUTH. 97 



BISMUTH. 

At a high temperature this metal is volatil- 
ized ; may be distilled in close vessels, and solidi- 
fies in foliated crystals. If it be merely melted in 
a crucible, and cautiously cooled, it crystallizes in 
well-defined cubes. Bismuth, as met with in com- 
merce, is not pure, for it generally contains iron 
and arsenic. In order to purify it, it is to be dis- 
solved in nitric acid ; the solution is to be decom- 
posed by water, and the precipitate, after being 
boiled in a solution of soda, is to be mixed with 
black flux, and moderately heated in a crucible. 

Bismuth combines with copper to form a pale- 
red brittle alloy. It forms a brittle compound with 
silver ; and it has been proposed as a substitute for 
lead, in refining silver. It is said to form a more 
fluid oxide, which penetrates the cupel more readily 
than that of lead ; and may also be used in smaller 
quantity. 

With mercury it forms a very fluid alloy, and 
makes the following metals brittle by combination : 
tungsten, palladium, rhodium, gold, and platina. 
9 



98 ON FRICTION. 

It is principally employed in making fusible alloys, 
and as an ingredient in solders. It is often called 
in the arts " tin glass." 



ON FRICTION. 

Friction is independent of the velocity ; at least 
when the velocity is neither very great nor very 
small. With hard substances, such as wood, metal, 
and stone, the amount of friction is simply as the 
pressure, without regard to surface, time, or velocity. 
Friction is greatest with soft, and least with hard 
substances. The diminution of friction by unguents 
depends on the nature of the unguents, without re- 
ference to the substances moving over them. 

The following table shows the comparative amount 
of friction of different metals, under an average 
pressure of 54.25 pounds to 69.55 pounds. 



TABLE OF FRICTION. 



99 



Names of Metals, Tried. 


Average 
Weight. 


Proportions. 


Weight per 
Square Inch. 




lbs. 




lbs. oz. 


Brass on Wrought Iron . . 


69.55 


7.312 


11 12.4 




69.55 


6.860 


11 12.5 


Brass upon Cast Iron . . . 


54.25 


6.745 


8 0.5 


Brass upon S-teel . . . . , 


69.55 


6.592 


11 12.5 


Hard Brass upon Cast Iron 


54.25 


6.581 


6 15.9 


Wro't Iron upon Wro't Iron 


69.55 


6.561 


11 12.5 


Cast Iron upon Cast Iron . 


54.25 


6.475 


8 0.5 


Do. do. Steel . . . 


i 69.55 


6.393 


11 12.5 


Do. do. Wro't Iron 


69.55 


6.023 


11 12.5 


Brass upon Brass 


69.55 


5.764 


11 12.5 




69.55 


3.305 


11 12.5 



From hence it would appear that hard metals 
have less friction than soft ones ; and that the fric- 
tion of hard against hard may be generally estimated 
at about one-sixth of the pressure. 

Relative to unguents, Sir John Rennie's experi- 
ments show that for gun metal or cast iron, with oil 
intervening, and a weight of 1120 pounds, the fric- 
tion amounted to J.63 of the pressure ; but on 
diminishing the insistent weights the friction was 
diminished to -^\. 33. 



100 ON BELLS. 



BELLS. 

The large bells now used in churches, are said 
to have been invented by Paulinus, Bishop of Nola, 
in Campania, about the year 400 : whence the 
"Nola" and " Campania" of the lower Latinity. 
They were probably introduced into England very 
soon after their invention. They are first mentioned 
by Bede, about the close of the seventh century. 
Ingulphus records that Turketul, Abbot of Croy- 
land, who died about the year 890, gave a bell of a 
very large size to that abbey, which he named Guth- 
lac. His successor, Egelric, cast a ring of six 
others, to which he gave the names of Bartholomew, 
Bettelin, Turketul, Tatwine, Pega, and Bega. Baro- 
nius informs us that Pope John XIII., A. d. 968, 
consecrated a very large new cast bell, in the Late- 
ran Church, and gave it the name of John. The 
ritual for the baptizing of bells may be found in the 
Boman Pontificale. 

The city of Nankin, in China, was anciently fa- 
mous for the largeness of its bells, as we learn from 
Father le Compte ; but they were afterwards far 
exceeded in size by those of the churches of Moscow. 



ON FLUXES. 101 

A bell in the tower of St. Ivan's Church, in Mos- 
cow, weighed 127,836 English pounds, or 57 tons 
1 cwt. 1 qr. 16 pounds. A bell given by the Czar 
Boris Goclunof to the Cathedral of Moscow, weighed 
288,000 pounds, or 128 tons 11 cwt. 1 qr. 20 lbs. 
And another, given by the Empress Anne, probably 
the largest in the known world, weighed 432,000 
pounds, or 192 tons 17 cwt. qrs. 26 pounds. 
According to Coxe (Travels in Russia, vol. 1, page 
322), the height of this last bell was 19 feet, the 
circumference at the bottom 63 feet 11 inches, and 
its greatest thickness 23 inches. The great bell of 
St. Paul's, London, weighs 12,000 pounds, and is 
9 feet in diameter. 

The largest bell in England, is " Great Tom,"of 
Christ Church, Oxford, which is 17,000 pounds 
weight. 



ON FLUXES. 

Black flux is made by mixing one part of 

powdered nitre with two parts of powdered argol, 

which is the commercial name for impure cream of 

tartar, or bitartrate of potash. 
9* 



102 ON FLUXES. 

This mixture is to be gradually thrown into a red- 
hot earthen crucible, so as to deflagrate it, taking 
care not to make the heat so high as to fuse the 
mixture. 

In this case, the nitric acid of the nitre is de- 
composed, its oxygen acts upon the carbon of the 
tartaric acid, carbonic acid is formed, and this unit- 
ing with the potash, both of the nitre and bitartrate, 
is converted into carbonate of potash. The whole 
of the carbon of the tartaric acid is not, however, 
so acted upon ; and the excess remains mixed with 
the carbonate of potash, in the state of finely divided 
charcoal. 

This flux should be immediately reduced to 
powder, and kept in a well stopped bottle ; other- 
wise it will become damp by the absorption of moist- 
ure, to which the carbonate of potash is subject. 
This flux is doubly useful ; the carbonate of potash 
combines with the earthy parts of the ore, such as 
silica and alumina, while the charcoal unites with 
the oxygen of the metallic oxides, and, carbonic 
acid being formed and expelled, the metal is reduced 
and melts. This flux is especially useful in the pro- 
cess of detecting arsenious acid, and reducing it to 
the metallic state. 

Argol, already described, is an impure bitartrate 



FUSING AND MELTING POINTS. 103 

of potash, powdered and mixed with the pulverized 
substance to be reduced, and is sometimes advantage- 
ously used as a flux. Owing to the intimate mix- 
ture of the charcoal and potash in this flux, a good 
deal of potassium is evolved ; and upon the reduc- 
ing property of this metal, the reduction of the 
oxides of other metals frequently depends to a con- 
siderable extent. 

Charcoal alone is, in the case of pure oxides, 
sometimes employed as a flux : thus, a crucible 
lined with charcoal is useful for the reduction of 
oxide of iron ; or the oxide may be mixed with char- 
coal. 

Sal-enixum, or the refuse from aquafortis, is an 
excellent flux for copper, &c. 



FUSING AND MELTING POINTS, ASCERTAINED BY MEANS 
OF PROFESSOR DANIEL'S REGISTERED PYROMETER. 



Mercury, . . . 


. —39° Fahrenheit 


Tin, 


. 442° Crichton. 


Bismuth, . . 


. . 497° do. 




. . 612° do. 




. . 773° Daniel. 



104 



FLUIDITY OF METALS. 



Antimony 
Silver, 
Copper, . 
Gold, . 
Cast iron, 



809° Daniel. 
1873° do. 
1996° do. 
2016° do. 

2787° do. 



Bismuth is mentioned by Agricola, about the year 
1529, A. D. It is of a reddish-white colour; its 
lustre is considerable, and its structure lamellated. 
It is so brittle as to be easily reducible to powder. 
When cold, its density is 9.83. It melts at 462°, 
according to Crighton, jr. ; Irving, 476° ; Daniel, 
497°. Thus even doctors disagree. Probably, 
however, the specimens experimented upon might 
have slightly varied as to quality — the reader is 
furnished with all the facts. 



FLUIDITY. 



According to Dr. Irving, the undermentioned 
bodies contain the annexed quantities of heat when 
rendered fluid : — 



ANTI-FRICTION METALS. 105 

Lead, 162° Fahrenheit. 

Zinc, 493° do. 

Tin, 500° do. 

Bismuth, .... 550° do. 



ANTI-FRICTION METALS. 

Many use 9 and 10 parts tin to 1 part copper. 

A superior composition to either of the above is, 
1 part copper, 1 part regulus of antimony, to 10 
parts of tin. Melt the copper first, then add the 
antimony, with a small portion of tin ; cover up the 
whole with charcoal for a short time prior to cast- 
ing ; add the remainder of the tin. These composi- 
tions are solely used for lining brass bearings. 

The following is an excellent anti-friction metal, 
not used for linings, but used in castings instead of 
brass: namely, 85 parts zinc, 10 parts tin, to which 
is added 5 parts of antimony. 



(103) 



TABLE FOR CONVERTING DECIMAL PROPORTIONS INTO DIVISIONS 
OF THE POUND AVOIRDUPOIS. 



Decimal. 


oz. dr. 


Decimal. 


oz. 


dr. 


Decimal. 


oz. 


dr. 


Decimal. 


oz. dr. 


.39 


1 


12.89 


2 


1 


25.39 


4 


1 


37.85 


6 1 


.78 


2 


13.28 


2 


2 


35.78 


4 


2 


38.28 


6 2 


1.17 


3 


13.67 


2 


3 


26.17 


4 


3 


38.67 


6 3 


1.5G 


4 


14.06 


2 


4 


26.56 


4 


4 


39.06 


6 4 


1.95 


5 


14.45 


2 


5 


26.95 


4 


5 


39.45 


6 5 


2.34 


6 


14.84 


2 


6 


27.34 


4 


6 


39.84 


6 6 


2.73 


7 


15.23 


2 


7 


27.73 


4 


7 


40.23 


6 7 


3.13 


8 


15.62 


2 


8 


28.13 


4 


8 


40.62 


6 8 


3.52 


9 


16.01 


2 


9 


28.52 


4 


9 


41.02 


6 9 


3.91 


10 


16.41 


2 


10 


28.91 


4 


10 


41.41 


6 10 


4.30 


11 


16.80 


2 


11 


29.30 


4 


11 


41.79 


6 11 


4.69 


12 


17.19 


2 


12 


29.69 


4 


12 


42.19 


6 12 


5.08 


13 


17.58 


2 


13 


30.08 


4 


13 


42.54 


6 13 


5.47 


14 


17.97 


2 


14 


30.47 


4 


14 


42.97 


6 14 


5.86 


15 


18.36 


2 


15 


30.86 


4 


15 


43.36 


6 15 


6.25 


1 


18.75 


3 





31.25 


5 





43.75 


7 


6.64 


1 1 


19.14 


3 


1 


31.64 


5 


1 


44.14 


7 1 


7.03 


1 2 


19.53 


3 


2 


32.03 


5 


2 


44.53 


7 2 


7.42 


1 3 


19.92 


3 


3 


32.42 


5 


3 


44.92 


7 3 


7.81 


1 4 


20.31 


3 


4 


32.81 


5 


4 


45.31 


7 4 


8.20 


1 5 


20.70 


3 


5 


33.20 


5 


5 


45.70 


7 5 


8.50 


1 6 


21.09 


3 


6 


33.59 


5 


6 


46.09 


7 6 


8.98 


1 7 


21.48- 


3 


7 


33.98 


5 


7 


46.48 


7 7 


9.38 


1 8 


21.88 


3 


8 


34.37 


5 


8 


46.87 


7 8 


9.77 


1 9 


22.27 


3 


9 


34.69 


5 


9 


47.27 


7 9 


10.16 


1 10 


22.66 


3 


10 


35.16 


5 


10 


47.66 


7 10 


10.55 


1 11 


23.05 


3 


11 


35.55 


5 


11 


48.05 


7 11 


10.94 


1 12 


23.44 


3 


12 


35.94 


5 


12 


48.44 


7 12 


11.33 


1 13 


23.83 


3 


13 


36.33 


5 


13 


48.83 


7 13 


11.72 


1 14 


24.22 


3 


14 


36.71 


5 


14 


49.22 


7 14 


12.10 


1 15 


24.61 


3 


15 


37.11 


5 


15 


49.61 


7 15 


12.50 


2 


25.00 


4 





37.50 


6 





50.00 


8 

> 



Application of the Table. 
The Chinese Packfong, similar to our German silver, accord 
ing to Dr. Fyfe's analysis, page 108, is said to consist of— 
40.4 parts of Copper 

equivalent to 



Zinc 

Nickel 

Iron 



6 oz. 

4 — 

5 — 



7 drams, full. 
1 — full. 
1 — nearly. 
7 — nearly. 



100.0 Parts. 



16oz.O 



Avd. 



STATUE COMPOSITION. 107 



KELLER S STATUE COMPOSITION. 

The brothers Keller, who were very celebrated 
statue founders, used an alloy, 10,000 parts of which 
contained 9140 parts of copper, 714 parts tin, 118 
parts zinc, and 28 parts lead. This is the composi- 
tion of the statue of Louis XIV., which was cast 
at a single jet, by Balthazar Keller, in 1669. It is 
twenty-one feet high, and weighs 53,263 French 
pounds. These statues are usually miscalled bronze. 

The best brass consists of four parts of copper to 
one part of zinc. 

Bronze was well known to the Romans under the 
name of " orichalcum" who took advantage of its 
resemblance to gold, in robbing the temples and 
other public places of that precious metal. Thus 
Julius Caesar robbed the Capitol of 3000 pounds 
weight of gold ; and Vitellius despoiled the temples 
of their gifts and ornaments, and replaced them 
with this inferior metal. 



106 



PACKFONG AND COPPER. 



THE CHINESE PACKFONG,* 

According to Dr. Fyfe's analysis, is said to con- 
sist of 



40.4 parts of copper 



25.4 
31.6 

2.6 " 



a 



100.0 parts. 



zinc 

nickel 

iron 



equiva- 
lent to 



f 6 oz. 7 dr. full. 

4 oz. 1 dr. full. 

5 oz. 1 dr. nearly. 

7 dr. nearly. 



16 oz. dr. 



COPPER. 



Copper, when mixed with as much zinc as possi- 
ble, that is 89 pounds copper to 100 pounds zinc, 
becomes white. The best " Goslar zinc" is from the 
Hartz, Germany. 



* Similar to our German silver. 



COMPOSITIONS. 109 



SILVER STEEL. 



1 part silver, 500 parts steel, according to Fara- 
day and Stodan. This alloy would be superior to 
the best steel. Steel also combines "with other 
metals, such as nickel, platinum, manganese, &c. 



COPPER AND ANTIMONY. 



75 parts copper, and 25 parts antimony. This 
alloy is brittle, lamellated, of a violet colour, sus- 
ceptible of a fine polish, and is more fusible than 
copper. 



ANTIMONY AND TIN, COPPER AND BISMUTH. 

100 parts of tin, 8 parts of antimony, 4 parts of 
copper, and 1 part of bismuth, constitute the com- 
pound commonly called pewter. 
10 



] 10 COMPOSITIONS. 



BISMUTH AND LEAD. 

1 part of bismuth, and 1 part of lead, a very te- 
nacious alloy, melting at 165° Centigrade, equiva- 
lent to 370° Fahrenheit. 

2 parts of lead to 1 part of bismuth, gives an 
alloy which dilates powerfully at the time of cooling. 
(This property makes it extremely suitable to all 
castings in which the greatest sharpness and finish 
are desirable. — H. Meigs.) 



FULL MEASURE OF CAPACITY OF TIN AND LEAD. 

82 parts tin, and 18 parts lead. 



BRILLIANTS OF FAHLUN, 

Thus called, are made from 29 parts of tin, and 
19 parts of lead. A very fusible and brilliant alloy. 



COMPOSITIONS OF METALS. Ill 



QUEEN S METAL, 

Imitating silver, has great metallic lustre : 9 
parts tin, 1 part lead, 1 part antimony, and 1 part 
bismuth. 



TIN AND ZINC. 



1 part tin, and 1 part zinc, is almost as tenacious 
as brass, and melts at 460° to 500° Centigrade, 
900° Fahrenheit. 



TIN AND IRON. 



These two metals may be alloyed in all propor- 
tions. 35 parts of tin to 65 parts of iron, form an 
alloy of a clear crystalline gray, and so brittle that 
it may be reduced to an impalpable powder. 



]12 SILVERING COPPER— MOSAIC GOLD. 



TO SILVER COPPER. 

Precipitate silver from its nitric solution by the 
immersion of polished plates of copper. Take of 
this silver 20 grains, supertartrate of potass, 2 
drachms, common salt, 2 drachms, and of alum, 
half a drachm. Mix the whole well together. 

Then take the article to be silvered, clean it well, 
and rub some of the mixture, previously a little 
moistened, upon its surface. The silver surface may 
be polished with a piece of soft leather. 

The dial-plates of clocks, scales of barometers, 
&c, are plated thus. 



MOSAIC GOLD (or molu), 

May be thus made : take copper and zinc, equal 
parts ; mix them together at the lowest possible 
temperature at which copper will fuse, and stir 
until a perfect mixture of the metals is effected. 
Then add gradually small portions of zinc at a time, 
until the alloy acquires a proper colour, which is 



BRONZING BRASS. 113 

perfectly white while in the melted state. It should 
then at once be cast into figured moulds. This 
alloy should contain from 52 to 55 per cent, of zinc. 



TO BRONZE BRASS, ETC. 

To 6 pounds of muriatic acid, add 2 pounds of 
oxide of iron, and 1 pound of yellow arsenic. Mix 
all well together, and let it stand for two days, fre- 
quently shaking it in the mean time, when it is fit 
for use. 

Whatever may be the article which requires 
bronzing, let it be perfectly cleaned, and free from 
grease ; immerse it in the above solution, and let it 
stand for three hours, or rather till it will turn en- 
tirely black. Then wash the spirits off, and dry it 
in sawdust, which has been found the best. 

After the article is perfectly dry, apply to it some 
wet black, the same as used for stones, and then 
polish it with some dry black-lead and a brush, and 
it is ready for lacquering. 



10* 



114 LACQUERS. 



LACQUERS. 

Lacquers are used upon polished metals and wood, 
to impart the appearance of gold. As they are want- 
ed of different depths and shades of colours, it is best 
to keep a concentrated solution of each colouring 
ingredient ready, so that it may at any time be 
added to produce any desired tint. 

1. Deep G old-coloured Lacquer. — Seed lac, three 
ounces ; turmeric, one ounce ; dragon's blood, a 
quarter of an ounce; alcohol, one pint. Digest for 
a week, frequently shaking. Decant and filter. 

2. Gold-coloured Lacquer. — Ground turmeric, 
one pound; gamboge, an ounce and a half; gum- 
sandarach, three pounds and a half ; shell lac, three- 
quarters of a pound (all in powder) ; rectified spirits 
of wine, two gallons. Dissolve, strain, and add one 
pint of turpentine varnish. 

3. Bed-coloured Lacquer. — Spanish anatto, three 
pounds ; dragon's blood, one pound ; gum-sandarach, 
three pounds and a quarter; rectified spirits, two 



LACQUERS. 115 

gallons; turpentine varnish, one quart. Dissolve 
and mix as the last. 

4. Pale Brass-coloured Lacquer. — Gamboge, cut 
small, one ounce ; cape aloes, ditto, three ounces ; 
pale shell lac, one pound ; rectified spirits, two gal- 
lons. Dissolve and mix as No. 2. 

5. Seed lac, dragon's blood, anatto, and gamboge, 
of each a quarter of a pound ; saffron, one ounce ; 
rectified spirits of wine, ten pints. Dissolve and 
mix as No. 2. 



The following receipts make most excellent lac- 
quers. 

1. Gold Lacquer. — Put into a clean four-gallon 
tin 1 pound of ground turmeric, 1-J ounces of 
powdered gamboge, 8J ounces of powdered gum-san- 
darach, f of a pound of shell lac, and 2 gallons of 
spirits of wine. After being agitated, dissolved, and 
strained, add one pint of turpentine varnish, well 
mixed. 

2. Bed Lacquer. — 2 gallons of spirits of wine, 
1 pound of dragon's blood, 3 pounds of Spanish 



116 ' LACQUERS. 

anatto, 3J pounds of gum-sandarach, 2 pints of tur- 
pentine. Made as No. 1 lacquer. 

3. Pale Brass Lacquer. — 2 gallons of spirits of 
wine, 3 ounces of cape aloes cut small, 1 pound of 
fine pale shell lac, 1 ounce of gamboge cut small, 
no turpentine varnish. Made exactly as before. 

But observe, that those who make lacquers, fre- 
quently want some paler, and some darker, and 
sometimes inclining more to the particular tint of 
certain of the component ingredients. Therefore, 
if a four-ounce phial of a strong solution of each 
ingredient be prepared, a lacquer of any tint can 
be procured at any time. 

4. Pale Tin Lacquer. — Strongest alcohol, 4 
ounces ; powdered turmeric, 2 drachms ; hay saf- 
fron, 1 scruple ; dragon's blood in powder, 2 scru- 
ples ; red saunders, J scruple. Infuse this mixture 
in the cold for 48 hours, pour off the clear, and 
strain the rest ; then add powdered shell lac, J 
ounce ; sandarach, 1 drachm ; mastic, 1 drachm ; 
Canada balsam, 1 drachm. Dissolve this in the 
cold by frequent agitation, laying the bottle on its 
side, to present a greater surface to the alcohol. 
When dissolved, add 40 drops of spirits of tur- 
pentine. 



LACQUER AND BRONZE LIQUID. 117 

5. Another Deep Gold Lacquer. — Strongest alco- 
hol, 4 ounces ; Spanish anatto, 8 grains ; powdered 
turmeric, 2 drachms ; red saunders, 12 grains. In- 
fuse and add shell lac, &c, as to the pale tin lac- 
quer ; and when dissolved add 30 drops of spirits 
of turpentine. 

N. B. Lacquer should always stand till it is quite 
fine, before it is used. 



GREEN BRONZE LIQUID. 

Take one quart of strong vinegar, half an ounce 
of mineral green, half an ounce of raw umber, half 
an ounce of sal-ammoniac, half an ounce of gum 
arabic, two ounces of French berries, half an ounce 
of copperas, and about three ounces of green oats, 
if these can be procured, although, if they cannot, 
the preparation will succeed perfectly well without 
them. Dissolve the whole in a strong earthen ves- 
sel, adding the berries and the oats, over a gentle 
fire ; bring the compound to boil, then allow it to 
cool, and run it through a flannel bag, when the 
bronze will be ready for use. 



118 SILVERING IVORY AND ZINCING. 



TO SILVER IVORY. 

Immerse a slip of ivory in a weak solution of 
nitrate of silver, and let it remain until the solution 
has imparted to it a deep yellow colour. Then take 
it out, and immerse it in a tumbler of clear water, 
and expose it in the water to the rays of the sun. 
After it has been exposed thus for about three hours, 
the ivory acquires a black colour, which on being 
burnished soon becomes a brilliant silver one. 



ZINCING. 



Copper and brass vessels may be covered with a 
firmly adherent layer of pure zinc, by boiling them 
in contact with a solution of chloride of zinc, pure 
zinc turnings being at the same time present in con- 
siderable excess. The same object may be attained 
by means of zinc, and a solution of sal-ammoniac, 
or caustic potassa. * 



TABLES. 



119 



TABLE I. — METAL PLATES. 

This table shows the weight of a square foot 
of different metal plates, of thicknesses of one six- 
teenth of an inch ' to one inch, advancing by a 
sixteenth : — 



Six- 


Wrought 


Cast 


Cast 


Cast 


Cast 


Cast 


Cast 


Cast 


teenths. 


Iron. 


Iron. 


Copper. 


Brass. 


Lead. 


Ziuc. 


Tin. 
lbs. 


Silver. 
lbs. 




lbs. 


lbs. 


lbs. 


lbs. 


lbs. 


lbs. 


1 


2.5 


2.3 


2.9 


2.7 


3.7 


2.3 


2.4 


3.4 


2 


5.1 


4.7 


5.7 


5.5 


7.4 


4.7 


4.7 


6.8 


3 


7.6 


7.0 


8.6 


8.2 


11.1 


7.0 


7.1 


10.2 


4 


10.1 


9.4 


11.4 


11.0 


14.8 


9.4 


9.5 


13.6 


5 


12.7 


11.7 


14.3 


13.7 


18.5 


11.7 


11.9 


17.0 


6 


15.2 


14.0 


17.2 


16.4 


22.2 


14.0 


14.2 


20.5 


7 


17.9 


16.4 


20.0 


19.2 


25.9 


16.4 


16.6 


23.9 


8 


20.3 


18.8 


22.9 


21.9 


29.5 


18.7 


19.0 


27.3 


9 


22.8 


21.1 


25.7 


24.6 


33.2 


21.1 


21.4 


30.7 


10 


25.4 


23.5 


28.6 


27.4 


36.9 


23.4 


23.7 


34.1 


11 


27.9 


25.8 


31.4 


30.1 


40.6 


25.7 


26.1 


37.5 


12 


30.4 


28.1 


34.3 


32.9 


44.3 


28.1 


28.5 


40.9 


13 


32.9 


30.5 


37.2 


35.6 


48.0 


30.4 


30.9 


44.3 


14 


35.5 


32.9 


40.0 


38.3 


51.7 


32.8 


33.2 


47.7 


15 


38.0 


35.2 


42.9 


41.2 


55.4 


35.1 


35.6 


51.1 


1G 


40. G 


37.6 


45.8 


43.9 


59.1 


37.5 


38.0 


54.6 



TABLE II. — CAST METAL BALLS. 



Diam. — Ins. 


Iron. — lbs. 


Copper. — lbs. 


Brass. — lbs. 


Lead. — lbs. 


1 

2 


3 
1.1 


1 
6 

1.3 


3 

1.3 


3 
14 

1.7 


3 


3.7 


4.5 


4.3 


5.8 


4 


8.7 


10.7 


10.2 


13.8 


5 


17.0 


20.8 


19.9 


26.9 


6 


29.5 


35.9 


34.3 


46.4 


7 


46.8 


57.1 


54.5 


73.7 


8 


69.8 


85.2 


81.4 


110.1 


9 


99.4 


121.3 


115.9 


156.7 


10 


13G.4 


166.4 


159.0 


215.0 



120 



TABLES. 



TABLE III. — CAST IRON PIPES. 

This table shows the weight of cast iron pipes 
1 foot long, of bores from 1 inch to 12 inches diam- 
eter, advancing by J of an inch ; and of thicknesses 
from J inch to 1 J inch, advancing by J of an inch. 



Bore. 


K 


% 


M 


% 


% 


% 


1 


iy 8 


W± 


In. 


M.s. 


lbs. 


lbs. 


lbs. 


lbs. 


lbs. 


lbs. 


lbs. 


lis. 


1 


;;.l 


5.1 


7.4 


10.0 


L2.9 


16.1 


19.6 


23.5 


27.6 


m 


3.7 


6.0 


8.6 


11.5 


14.7 


18.3 


22.1 


26.2 


30.7 


VA 


4.3 


6.9 


9.8 


13.0 


16.6 


20.4 


24.5 


29.0 


33.7 


m 


4.9 


7.8 


11.1 


14.6 


18.4 


22.6 


27.0 


31.8 


36.8 


2 


5.5 


8.8 


12.3 


16.1 


20.3 


24.7 


29.5 


34.5 


39.9 


2^ 


6.1 


9.7 


13.5 


17.6 


22.1 


26.8 


31.9 


37.3 


43.0 


V/l 


6.7 


10.6 


14.7 


19.2 


23.9 


2S.9 


34.4 


40.0 


46.0 


2^4 


7.4 


11.5 


16.0 


20.7 


25.7 


31.1 


36.8 


42.8 


49.1 


3 


8.0 


12.4 


17.2 


22.2 


27.6 


33.3 


39.3 


45.6 


52.2 


&A 


8.6 


13.3 


18.4 


23.8 


29.5 


35.4 


41.7 


48.3 


55.2 


2>y 2 


9.2 


14.2 


19.6 


25.3 


31.3 


37.6 


44.2 


51.1 


58.3 


m 


9.8 


15.2 


20.9 


26.9 


33.1 


39.7 


46.6 


53.8 


61.4 


4 


10.4 


16.1 


22.1 


28.4 


35.0 


41.9 


49.1 


56.6 


64.4 


i\i 


11.1 


17.1 


2.3!4 


30.0 


36.9 


44.1 


51.6 


59.4 


67.6 


4M 


11.7 


18.0 


24.5 


31.4 


38.7 


46.2 


54.0 


62.1 


70.6 


m 


12.3 


18.9 


25.8 


33.0 


40.5 


48.3 


56.5 


64.9 


73.6 


5 


12.9 


19.8 


27.0 


34.5 


42.3 


50.5 


58.9 


67.6 


76.7 


5M 


13.5 


20.7 


28.2 


36.1 


44.2 


52.6 


61.4 


70.4 


79.8 


hYo 


14.1 


21.6 


29.5 


37.6 


46.0 


54.8 


63.8 


73.2 


82.8 


5M 


14.7 


22.6 


30.7 


39.1 


47.9 


56.9 


66.3 


76.0 


85.9 


6 


15.3 


23.5 


31.9 


40.7 


49.7 


59.1 


68.7 


78.7 


88.8 


6 K 


l<;.o 


24.4 


33.1 


42.2 


51.5 


61.2 


71.2 


81.2 


92.0 


G% 


16.6 


25.3 


34.4 


43.7 


53.4 


63.4 


73.4 


84.2 


95.1 


m 


17.2 


26.2 


35.6 


45.3 


55.2 


65.3 


76.1 


87.0 


98.2 


7 


17.8 


27.2 


36.8 


46.8 


56.8 


67.7 


78.5 


89.7 


101.2 


7^ 


18.4 


28.1 


38.1 


48.1 


58.9 


69.8 


81.0 


92.5 


104.3 


iy 


19.0 


29.0 


39.1 


49.9 


G0.7 


72.0 


83.5 


95.3 


107.4 


?% 


19.6 


29.7 


40.5 


51.4 


62.6 


74.1 


85.9 


98.0 


110.5 


8 


20.0 


30.8 


41.7 


52.9 


64.4 


76.2 


88.4 


100.8 


113.5 


8^ 


20.9 


31.7 


43.0 


54.5 


66.3 


78.4 


90.8 


103.5 


116.6 


sS 


21.7 


32.9 


44.4 


56.2 


68.3 


80.8 


93.5 


100.5 


119.9 


8% 


22.1 


33.6 


45.4 


57.5 


70.0 


82.7 


95.7 


109.1 


122.7 


9 


22.7 


34.5 


46.6 


59.1 


71.8 


84.8 


98.2 


111.8 


125.8 


9K 


23.3 


35.4 


47.9 


60.6 


73.6 


87.0 


100.6 


114.6 


128.9 


9>3 


23.9 


36.4 


49.1 


62.1 


75.5 


89.1 


103.1 


117.4 


131.9 


9?4 


24.6 


37.3 


50.3 


63.7 


77.3 


91.3 


105.5 


120.1 


135.0 


10 


25.2 


38.2 


51.5 


65.2 


79.2 


93.4 


108.0 


122.8 


138.1 


1014 


25.8 


39.1 


52.8 


66.7 


81.0 


95.6 


110.4 


125.6 


141.1 


10H 


26.4 


40.0 


54.0 


68.3 


82.8 


97.7 


112.9 


128.4 


144.2 


io?| 


27.0 


41.0 


55.2 


69.8 


84.7 


99.9 


115.4 


131.2 


147.3 


11 


27.6 


41.9 


56.5 


71.3 


86.5 


102.0 


117.8 


133.9 


150.3 


! 1 1 ■ 


28.2 


42.S 


57.7 


72.9 


88.4 


104.2 


120.3 


136.7 


153.4 


11)1 


28.8 


43.7 


58.9 


74.4 


90.2 


106.3 


122.7 


139.4 


156.4 


u$| 


29.5 


44.6 


60.1 


75.9 


92.0 


108.5 


125.2 


142.2 


159.5 
162.6 


12 


30.1 


45.6 


61.4 


77.5 


93.6 


110.6 


127.6 


145.0 



TABLES. 



121 



TABLE IV. — CAST METAL CYLINDERS.* 



Diam. — Ins. 


Iron. — lbs. 


Copper. — lbs. 


Brass. — lbs. 


1 

Lead. — lbs. 


1 


2.5 


3.0 


2.9 


3.9 


2 


9.8 


12.0 


11.4 


15.5 


3 


22.1 


27.0 


25.8 


34.8 


4 


39.3 


47.9 


45.8 


61.9 


5 


61.4 


74.9 


71.6 


96.7 


6 


88.4 


107.8 


103.0 


139.3 


7 


120.3 


146.8 


140.2 


189.6 


8 


157.1 


191.7 


183.2 


247.7 


9 


198.8 


242.7 


231.8 


313.4 


10 


245.4 


299.5 


286.2 


387.0 



TABLE V. — SPECIFIC GRAVITY AND WEIGHT OF 
MATERIALS. 



METALS. 


Specific 


Wt. of l 


"Wt. of 1 




Gravity. 


cubic foot. 


cubio inch. 




oz. 


lbs. 


oz. 


Antimony, cast .... 


6702 


418.9 


3.878 


Arsenic . 








5763 


360.2 


3.335 


Bismuth, cast 














9822 


613.9 


5.684 


Brass, cast 














8396 


524.8 


4.859 


Brass, wire . 














8544 


534.0 


4.944 


Bronze . 














8222 


513.4 


4.753 


Cobalt, cast 














7811 


488.2 


4.520 


Copper, cast 














8788 


549.3 


5.086 


Copper, sheet 














8915 


557.2 


5.159 


Copper, wire 














8S78 


554.9 


5.136 


Gold, pure . 














19258 


1203.6 


11.161 


Gold, hammered 














19362 


1210.1 


11.205 


Gold, standard 














17647 


1102.9 


10.230 


Gun metal 














8784 


549.0 


5.083 


Iron, bars wrought 














7786 


486.6 


4.506 


Iron, cast 














7207 


450.4 


4.171 


Lead, cast . 














11352 


709.5 


6.569 


Mercury, solid . 














15632 


977.0 


9.046 


Mercury, fluid 














13568 


848.0 


7.852 


Nickel, cast 














7807 


487.9 


4.518 


Platinum, pure 














19500 


1218.8 


11.285 


Platinum, hammered 














20336 


1271.0 


11.767 


Silver, pure 














10474 


654.6 


6.061 


Silver, hammered 














10511 


656.9 


6.083 


Silver, standard . 














10534 


65S.4 


6.096 


Steel, tempered 














7818 


488.6 


4.524 


Steel, soft . 














7833 


489.6 


4.533 


Tin, cast 














7291 


455.7 


4.244 


Type metal . 














10450 


653.1 


6.047 


Zinc, cast 








7190 


449.4 


4.161 



11 



* The cylinders are solid, each one foot in length. 



122 



SPECIFIC COHESION OF METALS. 






TABLE VI. — SPECIFIC COHESION AND STRENGTH OF 

METALS. 

In the following table of specific cohesion, the co- 
hesion of plate glass is assumed as unity. If any 
of the numbers in this table be multiplied by 9240, 
the product will express the force in pounds, which 
would tear asunder a bar of the corresponding ma- 
terial, of one inch square of transverse section. 
Thus, the specific cohesion of steel, razor temper, is 
15.927 ; whence the extreme cohesion of a bar one 
inch square is 15.92T X 9240 = 147,165.48 pounds. 





Specific cohesion. 


Antimony, cast 


0.113 


Bismuth, cast 


. 0.345 to 0.319 


Copper, wire 


6.606 


" cast, Barbary . 


2.396 


" " Japan 


2.152 


Gold, wire 


3.279 


cast • • < 


2.171 


Iron, wire 


12.004 to 9.108 


" bar 


. 8.964 to 5.839 


" " best quality 


7.006 


" " German, B R 


. 9.880 to 6.514 



SPECIFIC COHESION OF METALS. 



123 



Iron, bar, Swedish, L 
" " Liege 
" " German, L 
" " Spanish . 
" " Oosement 
" " fine grained 
" " medium fineness 
" " coarse grained 
" cast, French . 
" " German 
< " English 
Lead, milled . 
" wire 

" cast, English 
Platinum, wire 
Silver, wire . 

cast • • 

Steel, razor temper 

" soft . 
Tin, wire 
" cast, English block 
" " Banca . 
" " Malacca . 
Zinc, wire 
" patent sheet . 
" cast, Goslar . 



Specific cohesion. 

9.445 to 7.296 

8.794 to 6.621 

9.119 to 7.382 
8.685 

8.142 to 7.296 
5.306 
3.618 
2.172 

7.470 to 4.000 
7.250 

5.520 to 4.334 
0.354 

0.334 to 0.270 
0.094 

5.995 to 5.625 

4.090 

4.342 

. 15.927 

. 12.739 

0.757 

0.706 to 0.565 
0.391 
0.342 
2.394 
1.762 

0.312 to 0.286 



124 DIRECT COHESION OF METALS. 



TABLE VII. — DIRECT COHESION OF METALS. 

The numbers in this table of experiments express 
the direct cohesion of bars one inch square in tons, 
of 2240 pounds. 





Tons. 


lbs. 


Iron bar, cast horizontally 


8 


32 


" " vertically 


8 


69 


Cast steel, previously tilted . 


59 


93 


Blistered steel, reduced by hammer 


59 


43 


Shear " " " 


56 


97 


Swedish iron " " 


32 


15 


English " " " 


24 


93 


Hard gun metal .... 


16 


23 


Wrought copper, reduced by hammer 


15 


8 


Cast " " " 


8 


51 


Fine yellow brass .... 


8 


01 


Cast tin .... 


2 


11 


Cast lead ..... 





81 


Wrought iron, mean of 26 experiments, 






Brunei 31 


20 


" " 9 Brown 


29 


25 


" " 8 Telford 


25 


00 


Iron cable, " 13 Brown 


21 


25 



RESISTANCE OF METALS. 



125 



TABLE VIII. — RESISTANCE OF METALS TO PRESSURE. 

In this table of experiments the number of pounds 
are the weights required to crush cubes of one-quar- 



r inch in the edge. 






lbs. 


Iron, cast vertically 


11136 


" " horizontally . 


10114 


Copper, cast 


7318 


" wrought . 


6440 


Brass .... 


10304 


Tin, cast . 


966 


Lead, cast 


483 



TABLE IX. — RESISTANCE OF METALS TO TORSION. 

This table of experiments by Brandreth, exhibits 
only the relative resistance to torsion, that of lead 
being assumed as unity. 
11* 



126 



5 1 


SOLDERS. 






lbs. 


Cast steel 19.56 


Shear steel . 








17.06 


Blister steel . 








16.69 


English iron . 








10.13 


Swedish iron 








9.50 


Hard gun metal 








5.00 


Fine yellow brass 








4.69 


Copper . 








4.31 


Tin 








1.44 


Lead 








1.00 



GOLD AND SILVER SOLDERS. 

Hard Solder for Gold is prepared from gold and 
silver, or from gold and copper, or from gold, silver, 
and copper. 

Gold Solder. — 66.6 parts of gold, 16.7 parts of 
silver, and 16.7 parts of copper. 

Hard Solder for Silver. — Equal parts of silver 
and brass ; but made easier of fusion by the admix- 
ture of one-sixteenth of zinc. 



ON SOLDERS AND SOLDERING. 127 

Another Silver Solder. — 19 parts fine silver, 1 
part copper, 10 parts brass. 

Another Silver Solder. — 66.6 parts silver, 30.4 
parts copper, 3.4 parts brass. 



BRASS SOLDER. 

Brass mixed with a sixth, an eighth, or even one- 
half of zinc. 

Another Brass Solder. — 12 pounds copper, and 
11 pounds of zinc. 



METHOD OE SOLDERING GOLD AND SILVER. 

After the solder is cast into an ingot, it would 
be more ready for use if you were to draw it into 
small wire, or flat it between two rollers. After 
that cut it into little bits, then join your work 
together with fine soft iron wire, and with a camel's- 
hair pencil dipped in borax, finely powdered and 



128 TO CLEANSE AFTER SOLDERING. 

well moistened with water, touch the joint intended 
to be soldered, placing a little solder on the joint. 
Apply it on a large piece of charcoal, and with a 
blow-pipe and lamp blow upon it through the flame 
until it melts the solder, and it is done. 



TO CLEANSE SILVER AFTER IT IS SOLDERED. 

Make it just red hot, and let it cool ; then boil 
it in alum water, in an earthen vessel, and it will 
be as clean as when new. 



TO CLEANSE GOLD AFTER IT IS SOLDERED. 

Put it through the same process as silver, but, 
instead of alum-water, boil it in wine and sal-ammo- 
niac. 



SILVER-SOLDER FOR JEWELLERS. 

19 dwts. of fine silver, 1 dwt. of copper, and 10 
dwts. of brass. 



ALLOYS AND SOLDER. 129 



TRINKET COMPOSITION. 

75 parts gold, 25 parts copper, and a little silver. 



SILVER-PLATE AND MEDAL ALLOY. 

95 parts silver, and 5 parts of copper. 



GOLD COIN OF AMERICA ALLOY. 

90 parts gold, 2.5 silver, and 7.5 copper. 



SOLDER FOR IRON. 



Nothing here is necessary but good tough brass, 
with borax, applied, mixed with water to the con- 
sistence of cream. 



130 



SOLDERING AND BURNING METALS. 



SOLDERING AND BURNING METALS. 



Besides the more common processes of soldering, 
properly so called, the process of burning together 
must frequently be employed, as in making small 
additions to old castings, and repairing small defects 
in new ones. 

In operations of this kind, very high degrees of 
heat are often required. This caused the introduc- 
tion of the blow-pipe into the workshop. Perhaps 
the most powerful and convenient form of this in- 
strument is that invented in France, by Count de 
Richemont, and patented in England by Mr. Del- 
bruch. A figured description of the same, with its 
use explained, we now present to our readers. 




SOLDERING AND BURNING METALS. 131 

The elastic tube h supplies hydrogen from the 
generator, and the pipe a supplies atmospheric air 
from a small pair of double bellows 5, worked by the 
foot of the operator, and compressed by a constant 
weight iv ; the two pipes meet at the arch, and pro- 
ceed through the third pipe e to the small jet/, from 
whence proceeds the flame. All the connexions are 
by elastic tubes, which allow perfect freedom of 
motion, so that the portable blow-pipe is carried to 
the work. 

In soldering by the autogenous process, the works 
are first prepared and scraped clean as usual ; the 
hydrogen is ignited, and the size of the flame is pro- 
portioned by the stop-cock li; the air is then ad- 
mitted through a, until the flame assumes a fine 
pointed character, with which the work is united. 

The gas generator bears some resemblance to 
Pepys' gasometer. . When it is first charged, the 
stopper 1 is unscrewed, and the lower chamber is 
nearly filled with curly shreds of sheet zinc, and the 
stopper is replaced. The cover is now removed, and 
a plug with a long wire is inserted from the top into 
the hole near 3 ; the upper chamber is next filled 
with dilute sulphuric acid (1 acid and 6 water), 
until it is just seen through the central hole to rise 
above the plate immediately beneath it. This mea- 



132 AERO-HYDROGEN BLOWPIPE. 

sures the quantity of liquid required to charge the 
vessel without the risk of overflow. The plug is 
now withdrawn from 3, and the cocks 4, and h, 
being opened, the air escapes from the lower vessel 
by the pressure of the column of water which enters 
beneath the perforated bottom 5, upon which the 
zinc rests. The cocks 4 and li are now closed, and 
by the decomposition of the water hydrogen is gene- 
rated, which occupies the upper part of the lower 
chamber, and drives the dilute acid upwards, through 
the aperture 3, so as to place matters in the posi- 
tion of the engraving, which represents the gene- 
rator about two-thirds filled with gas. 

The gas issues through the pipe h when both 
cocks are opened, but it has to proceed through a 
safety-box, 6, in which the syphon-tube clips two or 
three inches into a little plain water, introduced at 
the lateral aperture 7 : by this precaution the con- 
tents of the gasometer cannot be ignited, as should 
the flame return through the pipe 7i, it would be in- 
tercepted by the water in the safety-box. After 
three or four days' constant work, the liquid be- 
comes converted into the sulphate of zinc, and is 
withdrawn through the plug 8 ; the vessel is then 
refilled with fresh dilute acid, as already explained, 
but the zinc lasts a considerable time. 



AERO-HYDROGEN BLOWPIPE. 133 

The generators are made of lead, or, where porta- 
bility and lightness are required, of copper washed 
with lead, and all the exposed parts of the brass 
work are washed and united with lead to defend 
them from the acid. Occasionally the air is likewise 
supplied by aerometers, or vessels somewhat resem- 
bling the gas generator, but which are only filled 
with common air, and therefore do not require the 
zinc or acid. 

The difference between the aero-hydrogen blow- 
pipe described above, and the oxy-hydrogen blow- 
pipe of Dr. Hare, is this : — in the latter the pure 
gases (oxygen and hydrogen) are mixed in the exact 
proportions of two volumes of hydrogen to one of 
oxygen — which quantities, when combined, con- 
stitute water, and during combination evolve the 
greatest amount of heat. The aero-hydrogen blow- 
pipe is supplied with common air and pure hydro- 
gen. 



12 



134 SOFT SOLDERS. 



SOFT SOLDERS. 

Tin and lead in equal parts. Easier of fusion 
still is tin, lead, and bismuth, in equal parts ; or 
one or two bismuth, one lead, and one tin, easier 
still. 

For soft soldering brass, tin-foil makes a fine 
juncture, applied between the joints, care being 
taken to avoid too much heat. This is most excellent 
for fine brass work. The tin-foil must be moistened 
in a strong solution of sal-ammoniac. 



A SOLDER FOR LEAD. 

2 parts lead and 1 part tin. Its goodness is tried 
by melting it and pouring the bigness of a dollar 
piece upon the table ; for if it be good there will arise 
little bright spots in it. Apply rosin when you use 
the solder. 



SOLDER, PEWTER, AND WHITE METAL. 135 



PLUMBER S SOLDER. 



1 part bismuth, 5 parts lead, and 3 parts tin. 
forms a compound of great importance in the arts. 



COMPOSITIONS OE PEWTER. 

1. 100 parts tin, 17 parts of antimony ; the French 
add a little copper. 

2. 12 pounds of tin, 1 pound of antimony, 4 
ounces of copper. 

3. 7 pounds of tin, 1 pound of lead, 6 ounces cop- 
per, 2 ounces zinc. Melt the copper first. 



WHITE METAL. 



10 ounces lead, 6 ounces bismuth, and 4 drachms 
of antimony ; or, 2 pounds of antimony, 8 ounces of 
brass, and 10 ounces of tin. 



136 COMPOSITIONS OF SOFT METAL. 



MOSAIC MIXTURE. 



Equal parts of tin, bismuth, and mercury, forms 
a metal used for various ornamental purposes. 



SILVERY-LOOKING METAL. 



A very fine silvery-looking metal is made from 
100 parts tin, 8 parts antimony, 1 part bismuth, and 
4 parts copper. 



METAL FOR FLUTE VALVE KEYS. 

4 ounces of lead and 2 ounces of antimony. 



GERMAN TITANIUM. 



2 drachms of copper, 1 ounce of antimony, and 
12 ounces of tin. 



COMPOSITIONS OF SOFT METAL. 137 



SPANISH TITANIUM. 

8 ounces of scrap iron or steel, 1 pound of anti- 
mony, and 3 ounces of nitre. 

The iron or steel must be heated to whiteness, 
and the antimony and nitre added in small portions. 
Two ounces of this compound are sufficient to harden 
one pound of tin. 



BRITANNIA METAL. 

4 ounces of plate brass, 4 ounces of tin ; when 
fused add 4 ounces of bismuth, and 4 ounces of an- 
timony. This composition is added at discretion to 
melted tin. 



COLUMBIA METAL. 



4J pounds of tin, \ pound of bismuth, \ pound of 
antimony, and \ pound of lead ; or, 100 pounds of 
tin, 8 pounds of antimony, 1 pound of bismuth, and 
12* 



138 TYPE METALS. 

4 pounds of copper. This alloy is used for making 
tea-pots, and other vessels which imitate silver. 



TYPE METAL. 

10 pounds of lead, and 2 ounces of antimony. 
The antimony is added when the lead is in a state 
of fusion. The antimony gives hardness to the lead, 
and prevents its contraction when cooling. 

For Small Types. — 9 pounds of lead, 2 pounds 
of antimony, and 1 pound of bismuth. The anti- 
mony and bismuth are added when the lead is melted. 
This alloy expands in cooling ; the mould is there- 
fore entirely filled when the metal is cold, and no 
blemish is found in the letters. Stereotype plates 
are formed of this alloy. Some employ tin instead 
of bismuth. 

Type Metal of the French Letter Founders. — 
Four-fifths of lead, and one-fifth of regulus of anti- 
mony. 

The letter founders of Berlin use 11 pounds of 



GERMAN SILVER. 139 

antimony, 25 pounds of lead, and 5 pounds of iron. 
Many add tin, copper, and brass ; while some make 
their types from 3 parts lead, to 1 of antimony. 



GERMAN SILVER. 

1. 25 parts nickel, 20 parts zinc, and 60 parts 
copper. If for casting add 3 parts of lead. 

2. 16 parts copper, 8 parts zinc, and 3J parts 
nickel. 

3. 8 parts of copper, 3 J parts of zinc, and 2 parts 
of nickel. 

4. 28 parts copper, 13 parts zinc, and 7J parts 
nickel. 

5. Copper, 8 parts ; zinc, 3 J parts ; nickel 3 
parts. 

This last is a very beautiful compound. It has 
the appearance of silver a little below standard. By 
some persons it is even preferred to the more ex- 



110 SPECULUM METALS. 

pensive compound. Manufacturers are strongly re- 
commended not to use a metal inferior to this. 



SPECULUM METAL. 

1. Copper, 64 parts ; grain tin, 29 parts. Melt 
the metals separately, under a little black flux. In- 
corporate thoroughly by stirring with a wooden 
spatula ; then run the metal in the mould, so that 
the face of the intended mirror may be downwards. 

2. Copper, 32 parts ; tin, 14 parts ; arsenic, 2 
parts. A very good metal. 

3. Copper, 32 parts; tin, 13J parts; arsenic, 1J 
parts. 

4. Copper, 32 parts; tin, 15 parts; arsenic, 2 
parts. Better than 2 and 3. 

5. Copper, 32 parts ; tin, 15 parts ; brass, 1 part ; 
silver, 1 part; arsenic, 1 part. A most excellent 
metal, and by far the whitest, hardest, and most re- 
flective metal I have ever yet met with. 



SPECULUM METALS. 141 

6. Copper, 6 parts; tin, 2 parts; arsenic, 1 part. 
Sir Isaac Newton's mixture. It is a compact metal 
enough, but very yellow when polished. 

7. Copper, 3 parts ; tin, 1J parts. Compact, and 
whiter than the last. 

8. Brass, 6 parts ; tin, 1 part. Compact, but too 
yellow. 

9. 2 parts of 7th composition, and 1 part of 8th. 
Compact, but much too yellow when polished. 7, 
8, and 9, are experiments by Professor Molyneux, 
F. R. S. 

10. Copper, 32 parts ; tin, 2 parts ; arsenic, 1 
part. A pretty good metal, but polishes too yellow. 
Professor Mudge's composition. 



142 REMARKS. 



REMARKS. 

In melting arsenic, nitre is a good flux for fixing 
it with other metals. 

In using iron filings in your compositions, use 
corrosive sublimate (viz. chloride of mercury) for 
fixing it. 

Powdered flint glass also makes a most excellent 
flux for copper, tin, and arsenic. 

No. 5. This metal, when broken, should appear 
of a bright, glassy, and quicksilver complexion. If 
it appears hard and of a dead white, more tin must 
be added. The copper will sometimes take sixteen 
ounces of tin, if it is very pure. If it appears bluish 
and rough, more copper or brass must be added. 

It is somewhat singular that arsenic, though par- 
ticularly recommended by Sir Isaac Newton, Dr. 
Olynthus Gregory, and others, for giving homo- 
geneity to metallic compositions, should be so hastily 
thrown aside by the founders. This imprudent dis- 
use of it, I can only attribute to the disagreeable 
fumes or vapours, which arise when it is introduced 
into the crucible, to the melted mixture, which may 
produce disagreeable effects upon the operators, if 



REMARKS. 143 

proper care be not taken to prevent them from 
being received into the lungs. All the precaution 
necessary, is to bruise the arsenic coarsely, and in- 
troduce it into the crucible with a pair of tongs, 
having tied it up in a piece of paper, giving it then 
a stir with a wooden spatula made of birch, during 
which time retaining your breath — avoid it till you 
can see no more vapours arise from the crucible, 
when the metal will be ready to pour. 

The common black flux is made of two parts of 
tartar, and one of nitre. 

I have always found from adding a small quantity 
of arsenic, viz., from one-half ounce to one ounce to 
the pound of metal, that it would considerably im- 
prove even porous metal, and make it harder, like- 
wise, as well as whiter. 

In making speculums, the casting should be taken 
from the mould red-hot, and put into a quantity of 
hot ashes to anneal it, or else it will break in the 
sand. Let it remain in the ashes till the whole be- 
comes cold. 

Professor Nevil Masculyne, speaking of arsenic, 
says — I have been assured by two ingenious experi- 
mental philosophers that the fumes of arsenic, even 
when the garlic smell is very strong, are not in the 
least prejudicial to the lungs. 



144 ' PLATINA. 



A careful study of the above remarks will be of 
inestimable advantage to the practical brass founder, 
saving him both loss of work, as well as loss of time. 



PLATINA. 

Mirrors for telescopes, &c, are made of pla- 
tina, of exquisite beauty. The Spaniards are in the 
habit of mixing it with iron, in order to form gun- 
barrels, which are said never to rust, and which are 
much stronger than iron barrels alone, as it gives to 
the iron a remarkable toughness. It forms a valu- 
able coating for copper and iron, and may hereafter 
become precious for the formation of coins and 
medals. 

Platina, in its malleable state, may be cut with a 
knife ; but with steel it forms an alloy not to be 
touched with a file. 

The nitro-muriatic acid is the proper solvent for 
platina. 



ARSENIC. 145 



ON THE PROPERTIES OF ARSENIC. 

Arsenic is a brittle metal, and, in the recent frac- 
ture, of a lively bright colour, between tin-white 
and lead-graj ; but on exposure to the air it soon 
loses its metallic lustre, and turns prismatic, dull, 
and at last black. Its specific gravity is, according 
to Professor Mudge, between 8.310 and 5.763, ac- 
cording to its texture. 

Its hardness surpasses that of copper, but its 
ductility is so little, and it brittleness so great, that 
it is readily converted into a powder by the hammer. 
It is entirely volatilized when heated to 356° Fahr. 
It sublimes in close vessels, and then crystallizes in 
tetrahedra, or octahedra. When heated with the 
excess of air, it emits a strong smell of garlic, and 
burns, with a bluish white flame. It combines with 
sulphur by fusion. It unites to phosphorus, and 
combines with most of the metals. 

Besides giving a white colour to copper, it renders 
many of the ductile metals brittle. "When mixed 
with hyper-oxygenated muriate of potash, it deto- 
nates strongly by the stroke of a hammer. It is 

soluble in hydrogen gas by heat. It does not decom- 
13 ' 



146 EXPERIMENTS. 

pose water alone ; it decomposes sulphuric acid by 
heat. The nitric and nitrous acid oxidate it rapidly. 
The muriatic acid attacks it with heat. The oxy- 
genated muriatic acid (now termed chlorine), when 
in a gaseous state, inflames it instantly. It is nearly 
unalterable by the fluoric, boracic, phosphoric, and 
carbonic acids. It unites with alkaline sulphurets 
and hydro-sulphurets. It is a deadly poison. 

If you insert a little arsenic, reduced to fine 
powder, between two polished plates of copper, and 
bind closely together with iron wire, and heat them, 
the inner surfaces of the copper plates will be ren- 
dered white by the arsenic. 

Experiment No. 1. Experimental proofs of the 
properties of arsenic. Arsenic burns and is vola- 
tilized by heat. — Introduce into a crucible, made 
red-hot in a coal fire, a small quantity of arsenic, 
and it will begin to burn and become volatilized. 
If this crucible be covered with another, and the 
joinings luted with clay, the arsenic will be found 
in the upper one in brilliant crystals. 

Experiment No. 2. — The union of arsenic with 
copper may likewise be effected by fusing 1 part of 
arsenic with 4 of copper, in a common crucible. 



FONTAINEMOREAU'S ALLOYS. 147 

The alloy produced is a white metal. It is neces- 
sary in this experiment to cover the substances in 
the crucible with common salt, to prevent the action 
of the air. 



FONTAINEMOREAU'S NEW" ALLOYS OF ZING, A SUB- 
STITUTE FOR BRONZE, COPPER, AND BRASS. 

An invention of a new alloy of zinc, with small 
proportions of other metals, found to possess very 
peculiar advantages, has lately been introduced into 
England, where it has been patented in the name 
of M. Fontainemoreau. It is likely to prove of 
great utility in the manufacture of machinery, and 
in castings relating to the fine arts. As a substi- 
tute for copper and bronze it already bids fair to be 
extensively adopted. 

The proportions of metals which have been found 
most advantageous in forming varieties of the alloy, 
after very numerous and extensive experiments, are 
as follows : — 

No. 1. Zinc, 90 parts; copper, 8 parts; cast iron, 
1 part ; lead, 1 part ; 100 parts. 



148 FO'NTAINEMOREAU'S ALLOYS. 

No. 2. Zinc, 91 parts ; copper, 8 parts ; lead, 1 
part ; 100 parts. 

No. 3. Zinc, 92 parts ; copper, 8 parts ; 100 
parts. 

No. 4. Zinc, 99 parts ; copper, 1 part ; 100 parts. 

No. 5. Zinc, 97 parts ; copper, 2J parts ; cast 
iron, J part ; 100 parts. 

No. 6. Zinc, 97 parts ; copper, 3 parts ; 100 
parts. 

No. 7. Zinc, 99J parts; cast iron, j- part; 100 

parts. 

No. 8. Zinc, 91 J- parts ; copper, 8 parts ; cast 
i 
iron, J part ; 100 parts. 

The proportions stated of any of these metals 
may be slightly varied, so long as by such variation 
the alloy is not made too brittle, or too soft. For 
instance, the proportion of copper may be varied 
from about 1 part to about 12 parts, in every hun- 
dred ; but any greater proportion of copper than 
this, and less than that used in forming common 
brass, would make the alloy brittle. The propor- 
tion of cast iron may be varied from about one- 
quarter of a part, to about two parts in every hun- 
dred. The proportion of lead may be varied from 
about one, to about twenty-four parts in every hun- 



FONTAINEMOREAITS ALLOYS. 149 

dred parts ; bat the presence of some third metal is 
necessary to produce a proper combination of the 
zinc and lead. Instead of pure copper, or any other 
of the simple metals before to be used, brass, or the 
other alloys formed of these metals, may be used. 
But where this is done, the quantity of copper and 
the simple metals contained in such alloys must be 
taken into account in calculating the relative pro- 
portions of simple metals which the new alloy is to 
contain in reference to the tables of component 
parts. 

The principal object of the addition of the small 
quantities of copper, cast iron, and lead to the larger 
proportions of zinc, is to change the manner of the 
crystallization of the zinc after it has been fused 
and set to cool. 

The new alloys are of a closer texture, more 
homogeneous, and malleable, than simple zinc, and 
some kinds of iron ; are less liable to oxidation, and 
of a much finer grain than zinc — somewhat resem- 
bling that of steel, especially when the allo3 r s are 
rolled. They are also easier filed than either zinc, 
copper, or brass, and the filings do not stick in and 
clog the file. 

N. B. By casting the new alloys in metallic 

moulds, their hardness and homogeneity is increased, 
13* 



150 BRONZING THE ALLOYS. 

and a sort of temper is imparted to them, resembling 
or approaching to steel. 

For the purpose of rendering the alloys which 
are of a silvery-gray colour, perfectly suitable as 
substitutes for copper, bronze, brass, and other 
metals, the colour proper to the metals of which 
they are intended to be substitutes, is imparted 
to them by means of any solution of copper. The 
hydrochlorate of copper is found to answer best — 

Firstly. — For giving the alloys a blackish-bronze 
colour, they are treated with a solution of the salt 
of copper, diluted with a considerable quantity of 
water, and a small quantity of nitric acid may be 
added. 

Secondly. — To impart a red or copper colour, add 
to the solution of salt of copper, liquid ammonia, 
and a little acetic acid. The salt of copper may 
be dissolved in the liquid ammonia. 

Thirdly. — To impart a brass, or antique bronze 
colour, either of the three following means may be 
adopted : 1. A solution of copper, with some acetic 
acid. 2. The means before described for copper 
colour, with a large proportion of liquid ammonia. 
3. Water acidulated with nitric acid, by w T hich 
beautiful bluish shades may be produced. It must 
be observed, however, that this last process can only 



BRONZING THE ALLOYS. 151 

be properly employed on the alloys which contain a 
portion of copper. 

In either of these methods of colouring, a solution 
of sal-ammoniac may be substituted for the liquid 
ammonia. The quantities of each ingredient have 
not been stated, as these depend upon the nature of 
the alloy, the shade or hue desired, and the dura- 
bility required. 

The blackish-bronze colour may be superadded to 
the reel or copper colour, whereby a beautiful light 
colour is produced on the prominent parts of the 
article bronzed, or on the parts from which the 
blackish-bronze colour may have been rubbed off. 

These new alloys may be used as substitutes for 
various metals now in general use, such as iron, in 
various parts of machinery ; iron, lead, tin, or cop- 
per, in pipes and tubes, and bronze, brass, and cop- 
per, in machinery and manufactories, as well as for 
most of the other purposes for which more expensive 
metals are employed. 






152 ON COVERING IRON WITH ZINC. 



ON ZINC AS A PROTECTIVE COVERING FOR IRON ; AND 
THE ADAPTATION OF THE PROCESS OF ELECTRO- 
DEPOSITION FOR THAT PURPOSE. BY F. PELLATT, 

ESQ. 

Read at the Institution of Civil Engineers, London. 

The object of this paper is to direct attention to 
the properties of zinc as a protecting coating to 
iron; to describe the processes already employed 
for this purpose ; the reason of their failure ; and 
the peculiar adaptation of the electro-deposition of 
the metal for the end desired. 

It would be a needless waste of time to say any- 
thing regarding the superior value of iron as a ma- 
terial ; but a few remarks respecting its chemical 
influences may not be misplaced. 

The cause of iron becoming corroded is its superior 
affinity for oxygen. If the iron and water are both 
pure, this is not, indeed, found to be the case ; but 
under ordinary circumstances, neither of these exist 
in a state of purity. The iron, therefore, owing to 
its own impurity, and that of the water, is subject 



ON COVERING IRON WITH ZINC. 153 

to a powerful destructive influence, which is best 
known to those most experienced in its use ; and 
there is no circumstance in which we can place iron 
to be free from the action of water, it being present 
in the air and earth. So powerfully is this metal 
affected in the earth, or in contact with some salts, 
that it loses all its essential properties, and is 
converted into a substance so soft that it may be 
scratched by a finger nail. These facts render it of 
the utmost importance that some means be obtained 
for its protection, which, at the same time, will not 
interfere with the natural properties of the iron. 
The substances hitherto used for protecting iron are 
tin and paint. These, as lasting coatings, are not 
effective. The tin being electrically negative to the 
iron, renders it a means of destruction, instead of 
protection, when any part of the iron is exposed. 
By the laws of electricity, when metals are in con- 
tact, the negative metal is protected at the expense 
of the positive. 

Circumstances, such as different chemical men- 
strua, may alter the relative electrical states of 
metals. But under all ordinary circumstances this 
rule holds good ; and zinc being the positive metal, 
it becomes, in consequence, a protector to the nega- 
tive metal, iron. This electrical property of zinc in 



154 ON COVERING IRON WITH ZINC. 

connexion with iron and other metals, has induced 
those to "whom it was known, to recommend it as a 
coating. The difficulty hitherto has been the ob- 
taining of zinc pure, and the application of it with- 
out injuring the texture of the iron. 

From the known qualities of zinc, it has been 
lately much employed for various purposes, but has 
entirely disappointed the expectations formed from 
its properties. The reason of this is, that no zinc 
of commerce is pure, and that the impurities 
existing are destructive to it, from the electrical 
law we have alluded to. The impurities existing, 
more or less, in all zinc, are lead, iron, arsenic, and 
one or two other metals, all of which are electrically 
negative to zinc ; the consequence being that every 
atom of impurity, in connexion with the zinc, forms 
a galvanic battery of many thousands, or rather 
millions, of pairs of plates, the impurities being pro- 
tected, and the zinc destroyed. 

It has no doubt surprised many who have made 
use of zinc, to find it in a few weeks or months, 
according to circumstances, perforated with small 
holes, and completely destroyed. We say according 
to circumstances, because the ordinary time zinc 
lasts depends not only on the amount of impurities 
contained in it, but also on the exciting fluid to 



ON COVERING IRON WITH ZINC. 155 

which it is subjected. Exposed to the action of 
water from the atmosphere, the destructive influence 
operates comparatively slowly ; but with more ex- 
citing fluids very rapidly. 

Thus, a roof erected in the neighbourhood of a 
vinegar distillery, was completely destroyed in six 
weeks; and vessels used for dairy purposes have 
lasted but a very short time, owing to the presence 
of acids — these causing a rapid galvanic action be- 
tween the zinc and its imparities. It is then quite 
evident that impure zinc, being itself valueless, can- 
not afford protection to any other metal. Now, the 
only process yet in use for the purpose of coating iron 
with zinc, is that of immersing the iron in melted zinc. 
This we conceive open to many objections. The iron 
by this process being raised to a temperature of at 
least 800°, causes it to combine with the zinc, form- 
ing an alloy on the surface, which changes its state, 
and becomes brittle. But upon this subject, we 
shall refer to the report made by M. Dumas to the 
French Academy. He says — 

" The zincing of iron, made by steeping iron in a 
bath of melted zinc, has many inconveniences ; be- 
sides, the iron combining with the zinc, constitutes 
a very brittle, superficial alloy. The iron loses its 
tenacity — a circumstance which is not perceived, 



156 ON COVERING IRON WITH ZINC. 

however, except in trying to zinc fine iron wire, or 
very thin plate. Besides, the surface, being covered 
with a layer of not very fusible metal, is always in- 
formed. Thus, fine iron wire cannot be zinced by 
this process, as it becomes fragile and deformed; 
bullets cannot be zinced, as. they become misshapen, 
and no longer of the same calibre." 

We have reason to believe that very nice manipu- 
lations, and annealing the iron after zincing, may 
remove some of M. Dumas' objections to this pro- 
cess. Still, two fatal objections, in our opinion, 
would exist to its use : first, the impossibility of ob- 
taining pure zinc, except at an enormous expense, 
the only process being sublimation or distillation; 
and secondly, the impossibility of retaining its 
purity, during the process of applying it to iron. 

Setting aside the fact of an alloy of iron and zinc 
being produced by the action of heated iron immersed 
in melted zinc, the presence of foreign matter neces- 
sary to retain the zinc in fusion, renders it impure ; 
these matters forming less fusible compounds, and 
zinc being very volatile, a great amount of waste is 
created. 

But it is well known to all those acquainted with 
the deposition of metals from soluble salts by the 
electro process, that pure metal only is deposited ; 






ON COVERING IRON WITH ZINC. 157 

so that this process is not open to the objection upon 
this head, which may be made to every other, more 
especially in treating a metal of so intractable a 
character as zinc. It is also applicable to all sizes 
and shapes of work, requires no expensive erections, 
and, what is important in large operations, may be 
performed anywhere, and by any person. 

Although the protecting influence of zinc (we of 
course speak of pure zinc) upon other metals is 
practically unknown, it has been well known to men 
of science ; and we shall take the liberty of quoting 
the opinions of some of the best chemists upon the 
subject ; bearing in mind that zinc is electrically 
positive to other metals, and as such protects them 
from oxidation at a very trifling loss to itself — and 
that, by a well known law of electrical science, one 
body being electrically excited, that body induces 
its opposite state in other bodies with which it is in 
contact. Keeping these three points in view, we 
would call attention to the following opinions : — Dr. 
Kane says, " Zinc preserves the other metals, even 
if it be iron, from oxidation ;" and, again, " Zinc, 
when exposed to the air even in presence of water, 
becomes covered with a varnish of a gray substance, 
probably a definite sub-oxide, which is not further 
14 



158 ON COVERING IRON WITH ZINC. 

altered by exposure." Professor Graham, alluding 
to iron in water, says, " Articles of iron may be 
completely defended from the injury occasioned in 
this way, by the more positive metal zinc, while the 
protecting metal itself washes away slowly;" and 
further, when speaking of zinc, " When exposed to 
air, or placed in water, its surface becomes covered 
with a gray film of sub-oxide, which does not 
increase ; and this film is better calculated to resist 
both the mechanical and chemical effects of other 
bodies than the metal itself, and preserves it." And 
Professor Daniel, in his new work, says, " That a 
plate of pure zinc, when immersed in water, speedily 
becomes dulled by the formation of a thin coat of 
oxide ; but the oxidation proceeds no further, be- 
cause the adhesion of the metal prevents a renewed 
contact of the metal and the water." 

From these authorities we notice that pure zinc 
has a double protecting influence, the iron being 
protected by the zinc, and the zinc by its own oxide, 
besides that peculiar galvanic influence induced by 
the positive state of the zinc with respect to the 
iron. With regard to the peculiar adaptation of the 
electro processes to the zincing of iron, we shall 
again quote from M. Dumas' Report. He says, 
" Manufacturers, and those concerned in military 



ON COVERING IRON WITH ZINC. 159 

affairs and the fine arts, will learn with interest that 
these processes enable us to zinc, in an economical 
manner, iron, steel, and cast iron, by means of the 
pile or battery, with the solution of zinc, by operat- 
ing without heat, and consequently not interfering 
with the tenacity of the metal ; by applying it in 
thin layers, and by thus preserving the general forms 
of the pieces, and even the appearance of their 
minutest details. The thinnest plate may receive 
this preparation without becoming brittle, and may 
be turned to account in roofing buildings." 

We hope these authorities fully support what we 
have asserted, that pure zinc affords a perfect pro- 
tection to iron, is not itself susceptible of rapid de- 
cay, and is easily applicable to the electro process. 
We are aware that other opinions upon this subject 
have been given ; some have almost denied its gal- 
vanic influence, and have reduced it to what they 
term a mere " tendency" whilst others have much 
overstated it. Effects which may be witnessed every 
day, prove that there is a secret galvanic agency at 
work when metals are in contact. Take, for in- 
stance, the decay of iron when in contact with lead. 
Every one has observed that iron railings let into 
stone work with lead, are much decayed within a 



1G0 ON COVERING IRON WITH ZINC. 

short space of the contact of those two metals, "while 
the remaining portion is comparatively sound. This 
effect is from the iron being positive to the lead, 
Which is therefore protected at the expense of the 
iron. 

It is matter of regret that zinc cannot be used with 
the same protecting property to articles in use at sea. 
This arises from its strong affinity for muriatic acid, 
thereby forming muriate of zinc, which being readily 
soluble is taken off" by the water, leaving a new sur- 
face of zinc to be acted on, thus rapidly destroying 
the zinc. 

In situations where the articles are not exposed 
to the run of salt water, the zinc will be found a 
protection. 

The zinced iron solders readily. All other metals 
may be treated by this process for ornamental pur- 
poses. Copper will be found very useful. The de- 
positions by alkaline solutions are perfectly firm, 
and not subject to the objection to which those made 
by acid solutions are: these being always insecure 
from the formation of an oxide upon the iron, in- 
duced by the acid of the solution. The deposited 
Copper may be bronzed or gilt, and will be found 
most useful for ornamental work. 



ON COVERING IRON WITH ZINC. 1G1 

Many specimens of zinced iron, some of which 
had been exposed to the action of the weather for 
months, were exhibited to the meeting, as well as 
specimens of iron coated with copper by the same 
process. 



14* 



162 



WATER IN PIPES. 



WATER IN PIPES. 

This table shows the quantity and weight of 
water contained in one fathom of length of pipes of 
different bores from 1 inch to 12 inches in diameter, 
advancing by J inch. The weight of a cubic foot 
of water is taken at 1000 ounces avoirdupois, and 
the imperial gallon at 10 lbs. 



Diameter in 


Quantitjr in 


Quantity in Im- 


Weight in lbs. 


inches. 


Cubic inches. 


perial gallons. 


Avoird. 


1 
2" 


14.14 


0.051 


0.51 


1 


50.55 


0.205 


2.05 


n 


127.23 


0.400 


4.00 


2 


220.19 


0.818 


8.18 


2| 


353.43 


1.278 


12.78 


3 


508.94 


1.841 


18.41 


SJ 


092.72 


2.500 


25.00 


4 


904.78 


3.272 


32.72 


4J 


1145.11 


4.142 


41.42 


5 


1413.72 


5.113 


51.13 


6J 


1710.00 


0.187 


01.87 


6 


2035.75 


7.303 


73.03 


8J 


2389.18 


8.041 


80.41 


7 


2770.88 


10.022 


100.22 


71 


3180.80 


11.505 


115.05 


8 


3019.11 


13.090 


130.90 


6J 


4085.04 


14.777 


147.77 


9 


4580.44 


10.507 


105.07 


Q 1 


5103.52 


18.459 


184.59 


10 


5054.87 


20.453 


204.53 


101 


0234.49 


22.550 


225.50 


11 


0842.39 


24.748 


247.48 


ih 


7478.50 


27.049 


270.49 


12 - 


8143.01 


29.452 


294.52 



ON CRUCIBLES. 163 



ON CRUCIBLES. 

The manufacture of crucibles is a branch of the 
potter's art, requiring great care to insure success ; 
and until lately, was at the best a very uncertain 
process. The chief requisites in a good crucible are, 
refractoriness in the strongest heats, capability of 
withstanding the corrosive effects of any substances 
that may be ignited in them, and the effects of sud- 
den alterations of temperature. They must also be 
composed of a material sufficiently solid in its texture 
to prevent the passage of the solid metal through its 
pores. 

The composition producing pots of the best qua- 
lity is formed by pure fire clay mixed with finely 
ground cement of old crucibles, to which is added a 
portion of black lead or plumbago. The clay is pre- 
pared in the same manner as observed in pottery 
generally. The vessels, after being worked to the 
proper conical shape, are slowly dried, and then 
baked in a kiln. 

The composition used in the Royal Foundry of 
Berlin is formed of eight parts in bulk of Stour- 
bridge clay and cement, five of coke, and four of 



164 ON CRUCIBLES. 

graphite or plumbago. Crucibles manufactured from 
this mixture are capable of withstanding the greatest 
possible heat in which wrought iron melts, being 
equal to from 150° to 155° Wedgewood. They also 
bear sudden cooling without cracking. In the Ber- 
lin foundry they have been employed for twenty- 
three consecutive meltings of seventy-six pounds of 
iron each, which perhaps is the most complete and 
trying test that could be adopted. 

Another composition is as follows : — 8 pounds 
Stourbridge clay, 4 pounds burned clay cement, 2 
pounds coke powder, and 2 pounds pipe clay ; the 
whole being compressed in moulds while in a pasty 
state. 

The Hessian crucibles from Great Almerode and 
Epterode, resist the action of fluxes, and are tole- 
rably lasting. They are made from a fire clay con- 
taining a small amount of iron, but no lime. This 
is incorporated with silicious sand. These crucibles 
are rather porous, but they resist the effect of saline 
and leaden fluxes, and are not liable to crack, but 
they melt below the fusing point of bar iron. 

The black lead crucibles bear a much higher heat. 
Their composition is two parts of graphite and one 
of fire clay; this is mixed into a pasty mass by 
means of water. The crucibles are baked slightly 



ON CRUCIBLES. 105 

in the kiln, but are not completely hardened until 
put in the furnace for use. They are of a smooth 
surface, and are consequently suitable for gold and 
the precious metals generally. These crucibles are 
perhaps the very best yet manufactured, and many 
of the brass founders throughout Europe, and, for 
aught I have yet seen to the contrary, all the brass 
founders of America, are adopting them in pre- 
ference to ordinary clay ones. 

Mr. Anstey's patent process for the manufacture 
of crucibles is as follows : — 2 parts of finely ground 
raw Stourbridge clay, and 1 part of the hardest gas 
coke, previously pulverized, and sifted through a 
sieve of one-eighth of an inch mesh, are mixed well 
together with water. This mixture is moulded on a 
revolving wooden block, somewhat similar to the 
process pursued in pot throwing, a gauge being 
used to regulate the thickness of the pot, and a cap 
of linen placed upon the core previous to the appli- 
cation of the clay, in order to prevent its adhering 
when removed. The pot is then dried in a gentle 
heat, and is not thoroughly completed until required 
for use. It is then warmed before a fire, and laid 
in the furnace, with the mouth downwards — the heat 
of the fire having been previously lowered by the 
application of fresh coke. It is gradually brought 



]66 PLUMBAGO. 

up to a red heat, reversed, and fixed in its proper 
position in the furnace, and is then ready to receive 
the charge of metal. 



PLUMBAGO. 

Plumbago, or black lead, of which pencils are 
made, is a compound of iron and carbon, in the pro- 
portion of 9 parts carbon to 1 of iron. It has 
nothing similar to lead about it, unless its inquinat- 
ing property, by which paper is so readily marked. 
In this combination we have a metallic alloy less 
cohesive than almost any other substance, mercurial 
amalgam excepted ; whilst the very same ingredients, 
in different proportions, produce another alloy, steel, 
which has properties diametrically opposite, as it 
is capable of cutting the hardest substances, with 
very few exceptions. The softest steel is harder 
than the hardest iron. 



HARDENING STEEL. 167 



HARDENING STEEL. 

The process of hardening steel is called temper- 
ing or attempering, and consists in that novel ar- 
rangement of the particles which is produced when 
steel, while hot, is plunged into cold liquids, as 
water. The colder the liquid, or the more sudden 
the operation of cooling, the harder will the steel 
be. 

Case-hardening is the superficial conversion of the 
surface of iron into steel, by heating it in contact 
with animal carbon, in close vessels. Bar iron is 
converted into steel in the same way, only that 
powdered charcoal is the substance in which it is 
imbedded. 



ON BORON. 






This is the basis of a substance which has been 
long and extensively used in the arts and in medi- 
cine, under the name of borax. It is found abund- 
antly in Thibet and in South America, but in a 



JG8 ON BOEON. 

state too impure to be used without refining. This 
was long a secret process practised by the Venetians 
and Dutch, who imported the crude salt into Europe, 
under the name of tincal. 

Borax has a sweetish taste, and is " soluble in 
twelve parts of cold, and two parts of boiling water." 
Its crystals are transparent, but effloresce and be- 
come opaque in a dry atmosphere ; and they appear 
luminous by friction in the dark. 

It melts at a heat a little above that of boiling 
water, and gives out its water of crystallization, 
after which it forms a spongy mass, well known as 
calcined borax. When further heated to ignition, 
it passes into a glassy-looking substance, known as 
glacial borax. 

Boracic acid is obtained in unlimited quantity 
from the lakes of Tuscany. The water requires 
simply to be evaporated until the acid solution has 
been sufficiently concentrated to afford crystals. 
The acid thus obtained is chiefly taken to M. 
Pay en's works, at Marseilles, where it is manu- 
factured into borax. 

Dry borax, at a high temperature, has the re- 
markable property of melting and vitrifying the 
metallic oxides into glasses of different colours. On 
this account it is a most useful reagent for the blow- 



ON BORON. 169 

pipe. With oxide of chrome it forms an emerald 
green glass, and with oxide of cobalt an intensely 
blue glass. 

Oxide of copper tinges it pale-blue ; oxides of iron, 
bottle-green ; oxide of tin, opal ; oxide of manganese, 
violet ; oxide of nickel, pale yellowish-green. With 
the oxides of silver and zinc, and with several of the 
earths, it forms white enamels. 

Borax, in consequence of this property of vitrify- 
ing the metallic oxides, is used to clean the surface 
of metals, in processes of soldering with hard solder, 
and of welding cast steel. 

It is also valuable in the fusion of metals to pro- 
tect their surface from oxidizement. And it is worthy 
of remark, that, when mixed with shell-lac, in the 
proportion of one part to five, borax renders that 
resinous substance soluble in water, and forms with 
it a species of varnish. 



15 



170 ON SULPHUR. 



ON SULPHUR. 



This element, popularly known as brimstone, 
stands sufficiently well characterized by its brittle- 
ness, non-metallic appearance, and peculiar yellow 
colour. As a combustible it is universally known. 
Exposed to a temperature of 218° it melts almost 
into a liquid. When heated a few degrees higher, 
it becomes tenacious ; and when heated to the tem- 
perature of 800°, it takes fire, burns away with a 
lambent blue flame, and leaves no residuum. As 
the temperature rises the flame becomes more white ; 
and in pure oxygen gas the combustion goes on with 
great brilliancy. 

If, while melted and viscid, sulphur be poured 
into cold water, it acquires somewhat the consist- 
ency of soft sealing-wax, and in this state it is very 
commonly used for taking impressions, from seals 
and medals. 

Native sulphur is brought into this country chiefly 
from Sicily, where it occurs in beds of a blue clay 
formation, occupying the central half of the south 
coast of the island, and extending inwards as far as 
the district of Etna. ■ Sulphur is also an abundant 
ingredient in various minerals : iron pyrites and 



ON SULPHUR. 171 

galena, sulphurets of iron and lead, are particularly 
abundant in some localities ; and at one time a large 
portion of the sulphur used in England was obtained 
from the copper pyrites of the mines of Anglesey. 
It was, however, less pure than the fine sulphur of 
Sicily, and other volcanic districts, being commonly 
mixed with arsenic and other metallic impregnations, 
which are difficult to separate. 

Sulphur is sometimes employed for cementing 
iron bars into stone ; and at present it is in repute 
for taking impressions of seals and cameos. When 
used for this purpose, it is commonly kept previously 
melted for some time, to give the casts the appear- 
ance of bronze. The principal consumption of it, 
however, is in the manufacture of sulphuric acid, 
gunpowder, and vermillion. 

When the end of a sulphur match is lighted, the 
flame emits copious fumes, which are a compound 
of oxygen and sulphur. These fumes are intensely 
acid to the taste ; they constitute what is called sul- 
phurous acid, the first of the combinations of sul- 
phur and oxygen. The gas has a strong affinity for 
the water, and the solution which it forms with it is 
known as liquid sulphurous acid. This, if left ex- 
posed to the air, absorbs more oxygen, and passes 
into sulphuric acid. 



172 SELENIUM. 

Sulphur also combines with hydrogen, forming 
the highly poisonous and offensive gas known as sul- 
phuretted hydrogen, and which not unfrequently 
contaminates the coal gas supplied to us for illumi- 
nation. Sulphur and carbon also combine, and form 
a beautifully transparent and colourless liquid, ex- 
ceedingly volatile, and giving off an odour the most 
foetid and nauseous which it is possible to conceive. 
Sulphur likewise enters into combination with metals, 
forming sulphurets, and is a most excellent flux in 
the making of brazing solder. 



SELENIUM. 

This is a rare elementary substance, nearly allied 
to sulphur in its properties, although it in some re- 
spects partakes of the nature of a metal. It was 
discovered by Berzelius, in 1817, in the refuse of 
an oil of vitriol manufactory, where it was derived 
from the iron pyrites employed in the works, and 
which contain a mixture in very minute proportions 
of a similar compound of selenium and iron. It has 
also been found sparingly in combination with seve- 



ON CHLORINE. 173 

ral other metals, as lead, cobalt, copper, and bis- 
muth ; and with sulphur, in the volcanic products 
of the Lipari Islands. 

It is separated from its combinations with diffi- 
culty, and hitherto only in minute quantities. When 
obtained free of admixture, selenium, at common 
temperatures, is brittle, solid, of a reddish-brown 
colour, and metallic lustre, without taste or smell. 
But when finely powdered the powder assumes a 
deep-red, inclined to purple. It softens at the tem- 
perature of 180° ; is pasty at 200°, and melts at a 
few degrees above the boiling point of water. When 
warm it exhales a strong odour of decayed horse- 
radish, and is so ductile that it may be drawn into 
threads, which are red by transmitted, but gray by 
reflected light. It boils at 600°, and in close vessels 
throws off deep-yellow vapours, which condense into 
black, metallic-looking drops. 



ON CHLORINE. 



Chlorine enters into numerous highly important 
and interesting combinations. Various bodies, when 
immersed in it when in a liquid state (that is, when, 
15* 



174 ON CHLORINE. 

submitted to a pressure of four atmospheres, it be- 
comes a yellow transparent liquid), take fire sponta- 
neously. A candle burns in it with a red flame, and 
a piece of phosphorus introduced into it, burns with 
a pale-white light. Copper, tin, zinc, antimony, and 
arsenic, when introduced into it in their leaves, or 
reduced to filings, take fire, and, combining with the 
gas, form compounds analogous to the oxides, and 
which are therefore called chlorides. Mercury also 
enters rapidly into combination with it, forming 
chloride of mercury, a substance better known as 
corrosive sublimate. 

The grand source of chlorine is the water of the 
ocean. This is an enormous solution of salt — a 
universally known and indispensable article of con- 
sumption with the human race ; an article, indeed, 
which seems to be essentially necessary to maintain 
the body in a healthy condition. Now this salt is a 
compound of chlorine and a metal. It is, in fact, a 
chloride, consisting, when pure, of 60 of chlorine, 
and 40 of sodium, in 100 parts; and whether it be 
obtained by evaporation of sea water, or be dug out 
of the salt mines of Wieliczka or North wich, it has 
the same composition. 



METALLIC OXIDES. 175 



Some of the minerals contain but one earth ; but 
minerals are found in which the earths are combined 
in different proportions, by processes which produce 
that apparently endless variety of objects which 
mineral nature presents for our contemplation. 

Science has of late years demonstrated that none 
of the earths are simple substances, that is, chemical 
elements. Sir Humphrey Davy has proved that 
none of them are entitled to that character, that 
they are in fact compounds of certain metals with 
oxygen — that is, metallic oxides. This has been 
shown by the very direct method of abstracting 
oxygen from them, and thereby separating the me- 
tallic base. Thus, alumina (being the basis of alum) 
is the oxide of a gray and hard metal like platinum, 
and which burns with great brilliancy when heated 
with access of air, and reproduces the earth by ab- 
sorption of oxygen from the atmosphere. 

It is very singular that soda, as distinguished from 
potash, has been known with us only of late years ; 
whereas it was familiar to the Greeks and Hebrews. 
It was also known in Egypt, where it is found na- 
tive, and is known by the name of natron — which 



176 METALLIC OXIDES. 

occurs in the Bible. Thus Jeremiah speaks of wash- 
ing in natron.* 

From the preceding summary we may reckon 
ourselves justified in concluding that the solid strata 
of our globe — that is, the superficial shell with which 
we are acquainted, if not the vast mass of the globe 
itself — are nothing more than masses of metals of 
different kinds, disguised by oxygen : that they are 
in fact oxides, and bear evidence, in many cases, of 
being the products of combustion. 

* Jeremiah, ii. 22. 



APPENDIX. 



(177) 



AN APPENDIX 



USEFUL AND VALUABLE RECEIPTS. 



TO BROWN GUN BARRELS. 

Take of nitric acid, half an ounce ; sweet spirit 
of nitre half an ounce ; blue vitriol, two ounces ; 
tincture of steel, one ounce. Mix all together in 
eight gills of water. Apply this mixture with a 
sponge, then heat the barrel a little, and move the 
oxide with a hard brush. This operation may be 
repeated a third and fourth time, till you have the 
brown required. 

It is then to be carefully wiped, and sponged with 

boiling water, in which there has been put a small 

quantity of potass. The barrel being taken from 

the water, must be made perfectly dry, and then 

rubbed smooth with a burnisher of hard wood ; 

afterwards heated to the height of boiling water, 

and varnished with the following varnish : — 

(179) 



180 VARNISH FOR GUN BARRELS. 

Varnish for gun barrels that have undergone the 
process of browning. 

Take of spirits of wine two parts, dragon's blood, 
powdered, three drachms ; shell-lac bruised, one 
ounce ; dissolve all together. This varnish being laid 
on the barrel, and become perfectly dry, must be 
rubbed with a burnisher to render it smooth and 
glossy. 



ETHEREAL SOLUTION OE GOLD. 

Saturate nitro-hydrochloric acid with pure gold. 
Crystallize, and with the crystals saturate water. 
Shake this aqueous solution in a phial with an equal 
volume of pure ether ; then two fluids will result, 
the lighter of which is the ethereal solution of gold, 
and may easily be separated. This must be kept in 
a darkened bottle, as by exposure to light it quickly 
decomposes, flakes of gold being deposited. 

Any substance moistened with this will receive a 
coating of metallic gold, and hence metals may be 
rendered not liable to corrosion. 

Even in the dark it cannot be preserved long, 
but undergoes slow decomposition. 



TINNING. 181 



TO COAT SMALL NAILS, ETC., WITH TIN. 

Put half an ounce of powdered tin (which may 
be procured of any operative chemist), into a com- 
mon Florence flask, pour on about two ounces of 
concentrated muriatic acid, and boil over a spirit 
lamp until the tin is dissolved. When cool, pour 
into any convenient vessel and dilute with about an 
equal bulk of pure water. Drop in the nails required 
to be coated, holding the vessel so that they may all 
fall to one side. Immerse a piece of sheet-copper 
into the solution, as far apart from the nails as pos- 
sible, and connect it with the latter by means of a 
piece of copper wire. The effect of this arrange- 
ment is the developement of a current of voltaic 
electricity, which causes a rapid decomposition of the 
fluid, and the deposition of tin on the surface of the 
nails. After being subjected to this treatment for 
about an hour, the nails will be found to have re- 
ceived a thick coating of metal, and may then be 
removed from the liquid, dried, and polished. 

Recourse is frequently had to the above process 
for the purpose of coating the nibs of steel pens 
with tin, in order to prevent them from rusting. It 
succeeds better than any other method ever tried. 
16 



182 BRONZING ELECTROTYPE CASTS. 



BRONZING ELECTROTYPE CASTS. 

Chemical Bronze. 

There are many modes of bronzing employed in 
the arts ; the intent of each is to bring out the work- 
manship of the object. The selection is entirely a 
matter of taste. To prevent too great a sameness 
of appearance in a cabinet, it is, perhaps, better not 
to confine oneself to a solitary method. 

A chemical bronze may be made by boiling two 
ounces of carbonate of ammonia with one ounce of 
acetate of copper, in half a pint of vinegar, till the 
vinegar is nearly evaporated. Into this, pour a 
solution consisting of sixty-two grains of muriate 
of ammonia, and fifteen grains and a half of oxalic 
acid, in half a pint of vinegar. Replace the vessel 
on the fire till the contents boil ; when cold, strain 
through filtering paper ; preserve the liquor for use. 
The remaining sediment may be again treated with 
another half pint of the solution. This preparation 
must only be applied to medals bright and clean. 

Dirty specimens may be polished by an article 
used in domestic economy, consisting of rotten- 
stone, soft soap, and water. The medal is to be 



BRONZING ELECTROTYPE CASTS. 183 

well rubbed with a hard brush dipped in this. Care 
must be taken not to scratch the medal. It must 
afterwards be washed in water and placed to dry; 
when dry, the application of the leather and plate- 
brush will produce the required polish. Medals may 
also be cleansed by dipping them in nitric acid, 
either concentrated or diluted. Wax and grease 
may be removed by boiling in pearl-ash and water, 
or by pouring the boiling ley on the medals. 

In applying the bronze, first warm the medal, then 
dip a camel-hair pencil into the liquor and brush the 
surface for half a minute ; immediately after, pour 
boiling water over it. Directly the medal is dry, 
rub its surface lightly with soft cotton very slightly 
moistened in linseed oil. Gentle friction with a 
piece of dry cotton will finish the operation. The 
colour produced by this means is red ; its tints vary 
according to circumstances. Medals bronzed thus 
must be examined occasionally before they are con- 
signed to the cabinet ; for if perchance the vinegar 
has not been perfectly washed away, they will be 
disfigured by the formation of a green powder, — the 
acetate of copper. Should this occur, it may be 
removed by means of the moist and dry cotton. 



184 BLACK LEAD BRONZE. 



BLACK LEAD BRONZE. 

A very beautiful bronze is obtained bj the simple 
application of plumbago. It is obtained in a few 
minutes, and with very little trouble. The tint ob- 
tained seems much to depend on the state of the 
surface of the original medal. Copies of some 
medals "take" the black lead better than those of 
others. To produce the tint in the greatest perfec- 
tion, the operation should be performed immediately 
after the medal is separated from the mould. Bright 
specimens from fusible moulds are best, but all others 
may be thus treated ; those taken from wax should 
be cleansed with pearlash or soda. 

The bronze is obtained by brushing the surface 
of the medal with plumbago, then placing it on a 
clear fire till it is made too hot to be touched, and 
applying a plate brush so soon as it ceases to be hot 
enough to burn the brush. A few strokes of the 
brush will produce a dark brown polish, approaching 
black, but entirely distinct from the well known 
appearance of black lead. If the same operation is 
performed on a medal that has been kept some days, 
or upon one that has been polished, a different, but 
very brilliant tint is produced. The colour is 



TO TIN IRON. 185 

between red and brown. The richness of colour 
thus produced is by many preferred to the true dark 
brown. 



CARBONATE OF IRON BRONZE. 

Beautiful tints are produced by using plate- 
powder or rouge. After moistening with water, it 
is applied and treated in precisely the same manner 
as the plumbago. 



TO TIN IRON. 

Metal to be tinned must be cleansed, if new work, 
by putting it in a pickle — a mixture of sulphuric 
acid and water — then scoured with sand, and cleansed 
in water : but if old, the pickle should be a mixture 
of muriatic acid and water. It is then ready for 
tinning. 

The article should be placed on the fire, and suf- 
ficient heat applied to melt the tin. Care should be 
taken that too great a heat should not be applied, or 

the article will be burned. It must be rubbed well 
16* 



186 LIQUID GLUE AND FIRE-CLAY. 

with a piece of sal-ammoniac placed between two 
wires, likewise some powder sprinkled upon it, to 
keep the metal from oxidating. Apply the tin, wipe 
it over with a piece of tow, then the work is finished. 



LIQUID GLUE. 

Shell-lac dissolved in wood naptha (the pyroxilic 
spirit of the chemists, and the naptha of the oil and 
colour shops) makes good liquid glue, water-proof, 
and not requiring the application of heat. A quarter 
of a pound avoirdupois of shell-lac to be dissolved in 
three ounces of naptha, apothecaries' measure. Put 
the former into a wide-mouthed bottle ; pour the 
latter upon it, and stir the mixture two or three 
times during the first thirty-six hours. 



ARTIFICIAL FIRE-CLAY. 



The fusibility of common clay arises from the pre- 
sence of impurities, such as lime, iron, and magnesia. 
These substances may be easily removed by steeping 



A VALUABLE CEMENT. 187 

in hot muriatic acid, then washing with water, and 
drying. Excellent crucibles may be made from 
common clay prepared in this manner. 



A CEMENT WHICH RESISTS THE ACTION OF FIRE AND 

WATER. 

Take half a pint of milk, mix with it an equal 
quantity of vinegar, so as to coagulate the milk ; 
separate the curds from the whey, and mix the lat- 
ter with the whites of four or five eggs, well beaten 
up. The mixture of these two substances being 
complete, add to them quick-lime, which has been 
passed through a sieve ; make the whole into a thick 
paste, to be of the consistence of putty when used. 

This cement has been applied to close the fissure 
of an iron cauldron for the boiling of pitch, and 
which has been in use for five years without requir- 
ing further repairs. 



188 CEMENT FOR THE JOINTS OF CAST IRON. 



CEMENT FOR THE JOINTS OF CAST IRON. 

Take of cast iron borings, 20 pounds ; flour of 
sulphur, 2 ounces ; muriate of ammonia, 1 ounce ; 
mix intimately in the dry state, and then add a suf- 
ficient quantity of warm water to render the whole 
quite wet. Press the mass together in a lump, and 
allow it to remain until such time as the combined 
action of the materials renders it quite hot, in which 
state it must be hammered, with proper tools, into 
the joints. 



NIELLO-METALLIC ORNAMENTS. 

Cover the object to be ornamented with an etch- 
ing ground similar to that employed by copper-plate 
engravers ; draw the ornament with a needle, and 
etch it by means of a corrosive acid ; then carefully 
remove the etching ground with the proper dissolv- 
ing fluids (such as oil of turpentine, ether, &c), and 
afterwards wash the object quite clean, and set for 



NIELLO-METALLIC ORNAMENTS, ETC. 189 

a moment with a weak acid. Place it now in a gal- 
vano-plastic apparatus, and leave it until it becomes 
galvano-plastically covered, that is, all the etched 
lines filled up. When all the lines and cavities are 
completely filled up in this way, and the deposit in 
them is 'equally high as, or yet higher than, the 
plain surface, the object must be taken out of the 
galvano-plastic apparatus, and the metallic layer, 
which has been raised by the operation, ground or 
planed off until brought to the same level with the 
metal of the object, leaving the etched lines or cavi- 
ties full. 

Of course, the metal of the object to be orna- 
mented and the metallic deposit must be different. 
The effect produced is extremely pretty, and the 
means cheap and simple. 



TRACING PAPER. 



Mix six parts (by weight) of spirits of turpentine, 
one of resin, one of boiled nut oil, and lay on with 
either a brush or sponge. 



190 TO FIX DRAWINGS. 



TO PIX DRAWINGS. 

A method which is equally simple and ingenious, 
of giving to drawings in pencils and crayons the 
fixidity of painting, and without injury, is obtained 
by spreading over the back of the paper an alcoholic 
solution of white gum-lac. This solution quickly 
penetrates the paper, and enters even into the marks 
of the crayon on the other side. 

The alcohol rapidly evaporates, so that in an 
instant all the light dust from the crayons and chalk, 
which resembles that on the wings of a butterfly, 
adheres so firmly to the paper, that the drawing may 
be rubbed and carried about without the least par- 
ticle being effaced. 

The following are the accurate proportions of the 
solution : 10 parts of common gum-lac are dissolved 
in 120 parts of alcohol ; the liquid is afterwards 
bleached with animal charcoal. 

For the same purpose may be used even the ready- 
made paint that can be purchased at the colour 
stores, containing a sixth of white-lac, and adding 
two-thirds of rectified spirits of wine. After it has 
been filtered, there is nothing further to be done 



USEFUL RECEIPTS. 191 

than to spread a layer of either of these solutions 
at the back of the drawing, in order to give them 
the solidity required. 



ANTIDOTE TO ARSENIC. 



Magnesia is an antidote to arsenic, equally effi- 
cacious with peroxide of iron, and preferable to it, 
inasmuch as it is completely innocuous in almost any 
quantity, and can be procured in any form. 



TO SOFTEN IVORY. 

Slice half a pound of mandrake and put it into 
a quart of the best vinegar, into which immerse your 
ivory. Let it stand in a warm place for 48 hours, 
and you will then be enabled to bend the ivory into 
any required form. 



TO SEPARATE THE METALLIC PORTION FROM GOLD 
AND SILVER LACE. 

Immerse the lace for a short time in nitric acid. 



]92 BLUEING AND GILDING STEEL. 



BLUEING AND GILDING STEEL. 

The mode employed in blueing steel is merely to 
subject it to heat. The dark blue is produced at a 
temperature of 600°, the full blue at 500°, and the 
blue at 550°. 

Steel may be gilded by the following process : to 
a solution of the muriale of gold, add nearly as 
much sulphuric ether. The ether reduces the gold 
to a metallic state and keeps it in solution, while the 
muriatic acid separates, deprived of its gold, and 
forms a distinct fluid. Put the steel to be gilded 
into the ether, which speedily evaporates, depositing 
a coat of gold on the metal by dint of the attraction 
between them. After the steel has been immersed 
it should be dipped into cold water, and the burnisher 
should be applied, which strengthens its adhesion. 
Figures, flowers, and all descriptions of ornaments 
and devices, may be drawn on the steel by using the 
ether with a fine camel-hair pencil, or writing pen. 



TO HARDEN STEEL DIES. 193 



TO HARDEN STEEL DIES. 

A vessel holding 200 gallons of water, is to be 
placed at the height of 40 feet above the room in 
which the dies are to be hardened. From this vessel 
the water is conducted through a pipe of one inch 
and a quarter in diameter, with a cock at the bottom, 
and nozzles of diiferent sizes to regulate the dia- 
meter of the jet of water. Under one of these 
place the heated dies, the water being directed on 
to the centre of the upper surface. By this process 
the die is hardened in a way as best to sustain the 
pressure to which it is to be subjected; and the 
middle of the face, which by the old process was 
apt to remain soft, now becomes the hardest part. 
The hardened part of the dies so managed, were it 
to be separated, would be found to be in the seg- 
ment of a sphere, resting in the lower softer part, 
as in a dish, the hardness, of course, gradually de- 
creasing as you descend towards the foot. Dies 
thus hardened, preserve their form till fairly worn 

out. 

17 



194 PORTABLE GLUE, ETC. 



PORTABLE GLUE. 

Boil one pound of the best Russian glue, and 
strain. Then add half a pound of brown sugar, and 
boil thick. When cold, the compound may be poured 
into small moulds, and afterwards cut into pieces. 

This glue is very soluble in warm water, and is 
particularly useful to artists for fixing their drawing- 
paper to the board. 



PREVENTION OF CORROSION. 

The best means of preventing corrosion of metals 
is to dip the articles first into a very dilute nitric 
acid, to immerse them afterwards in linseed oil, and 
to allow the excess of oil to drain off. By this pro- 
cess metals are effectually prevented from rust or 
oxidation. 



CEMENT AND SOLUBLE GLASS. 195 



CEMENT. 



Mix ground white lead with as much finely-pow- 
dered red lead as will make it of the consistence of 
soft putty. 



SOLUBLE GLASS. 

What is called soluble glass is now beginning to 
come into use as a covering for wood and other 
practical purposes. It is composed of 15 parts of 
powdered quartz, 10 parts of potash, and 1 part of 
charcoal. 

These are melted together, worked in cold water, 
and then boiled with 5 parts of water, in which it 
entirely dissolves. It is then applied to wood-work, 
or any other required substance. As it cools it 
gelatinises, and dries up into a transparent, colour- 
less glass, on any surface to which it has been ap- 
plied. It renders wood nearly incombustible. 



196 JAPANNING. 



JAPANNING. 

First. Provide yourself -with a small muller and 
stone, to grind any colour that you may require. 

Secondly. Prepare yourself with white hard var- 
nish, brown varnish, turpentine varnish, Japan gold 
size, and spirit of turpentine, which you may keep 
in separate bottles until required. 

Thirdly. Provide yourself with flake white, red 
lead, Vermillion, lake, Prussian blue, king's and 
patent yellow, orpiment, spruce and brown ochre, 
mineral green, verditer, burnt umber, and lamp- 
black. 

Observe that all wood- work must be prepared 
with size, and some coarser material mixed with it, 
in order to fill up and harden the grain of the wood 
— such, indeed, as may best suit the colour intended 
to be laid on — which must be rubbed smooth with 
glass-paper when dry ; but in case of accident it is 
seldom necessary to resize the damaged places 
unless they are considerable. 

With the foregoing colours you may match always 
any one in use for japanning, always observing to 
grind your colours smooth in spirit of turpentine ; 



JAPANNING. 197 

add a small quantity of turpentine and spirit varnish, 
and lay it carefully on with a camel's-hair brush, 
then varnish with brown or white spirit varnish, 
according to colour. 

For a black, mix up a little size and lamp-black, 
and it will bear a good gloss without varnishing 
over. To imitate black rosewood, a black ground 
must be given to the wood, after which take some 
finely levigated red lead, mixed up as before directed, 
and lay on with a flat, stiff brush, in imitation of 
the streaks in the wood ; after which take a small 
quantity of lake, ground fine, and mix it with brown 
spirit varnish, carefully observing not to have more 
colour in it than will just tinge the varnish ; but 
should it happen on trial to be still too red, you 
may easily assist it with a little umber, ground very 
fine, with which pass over the whole of the work 
intended to imitate black rosewood, and it will have 
the desired effect. If the work be done by a good 
japanner, according to the foregoing rules, it will, 
when, varnished and polished, scarcely be distin- 
guished from the real wood. 



17 



198 TO PRESERVE POLISHED STEEL, ETC. 



TO PRESERVE POLISHED STEEL FROM RUST. 

Mix some oil with caoutchouc; melt in a close 
vessel, stirring to prevent burning. A high tem- 
perature will be required. This will form a perfect 
air-proof skin over the surface, which may very 
easily be removed by brushing with warm oil of 
turpentine. 



CEMENT FOR ATTACHING METAL TO GLASS. 

Take two ounces of a thick solution of glue, 
and mix with one ounce of linseed oil varnish, or 
three-quarters of an ounce of Venice turpentine. 
Boil together, agitating until the mixture becomes 
as intimate as possible. The pieces cemented should 
be fastened together for the space of forty-eight or 
sixty hours. 



VARNISHES. 19f 



VARNISH FOR COLOURED DRAWINGS. 

Canada balsam, one ounce ; oil of turpentine, Ho 
ounces. Dissolve. Size the drawings first with a 
jelly of isinglass, and when dry apply the varnish, 
which will make them look like oil paintings. 



JAPANNERS COPA; GARNISH. 

Take of the best pale African copal, seven pounds ; 
fuse ; add two quarts of clarified linseed oil. Boil 
for a quarter of an hour, remove it into the open 
air, and add three gallons of boiling oil of turpen- 
tine. Mix well, then strain into the cistern, and 
cover up immediately. 



SOFT VARNISH. 



Callot's soft varnish for etching: — linseed oil, 
four ounces ; and half an ounce each of gum benzoin 
and white wax. Boil to two-thirds. 



200 VARNISHES. 



HARD VARNISH. 



Callot's hard varnish for etching : — Take four 
ounces each of linseed oil and mastic, and melt to- 
gether. 



FLEXIBLE VARNISH. 



Flexible varnish for balloons, &c. : — India-rubber 
in shavings, one ounce ; mineral naptha, two pounds. 
Digest at a gentle heat in a close vessel until dis- 
solved, then strain. 



FRENCH POLISH. 

Dissolve one part of gum-mastic, and one part 
of gum-sandarach, in forty parts of spirits of wine, 
and then add three parts of shell-lac. This process 
may be performed by putting the ingredients into a 
loosely corked bottle, and then placing it in a vessel 



VARNISHES. 201 

of water a little below 173° Fahrenheit, or the boil- 
ing point of spirits of wine, until the solution be 
effected. 



BRUNSWICK BLACK. 

Foreign asphaltum, forty-five pounds; drying 
• oil, six gallons; and litharge, six pounds. Boil for 
two hours, then add dark gum amber (fused), eight 
pounds ; hot linseed oil, two gallons. Boil for two 
hours longer, or until a little of the mass, when 
cooled, may be rolled into pills. Then withdraw 
the heat, and afterwards thin down with twenty-five 
gallons of oil of turpentine. Used for iron-work, &c. 



MORDANT VARNISH. 



Take one ounce of mastic, one ounce of sanda- 
rach, half an ounce of gum-gamboge, and a quarter 
of an ounce of turpentine. Dissolve in six ounces 
of spirits of turpentine. 



202 VARNISHES. 



ANOTHER. 

Place a quantity of boiled oil in a pan, and sub- 
ject it to a strong heat. When a disengagement of 
black smoke takes place, set it on fire, and in a few 
moments extinguish it, by covering over the pan. 
Then pour the matter while heated into a bottle, 
previously warmed, adding to it a little oil of tur- 
pentine. 



ANOTHER. 



Mix asphalte and drying oil, diluted with oil of 
turpentine. For bronzing, or very pale gilding. 



ANOTHER. 



Take a quantity of camphorated copal varnish, 
and add a little red lead. 



VARNISHES. 203 



ANOTHER. 



Dissolve a little honey in thick glue. For gild- 
ing, &c. 



SUPERIOR GREEN TRANSPARENT VARNISH. 

The beautiful, transparent green varnish em- 
ployed to give a fine glittering colour to gilt or 
other decorated work, may be prepared as follows : 
Grind a small quantity of Chinese blue with about 
double the quantity of finely powdered chromate of 
potash, and a sufficient quantity of copal varnish 
thinned with turpentine. The mixture requires the 
most elaborate grinding or incorporating, otherwise 
it will not be transparent, and therefore useless for 
the purpose to which it is intended. The "tone" 
of the colour may be varied by an alteration in the 
proportion of the ingredients. A preponderance of 
chromate of potash causes a yellowish shade in the 
green, as might have been expected; and vice versa 
with the blue, under the same circumstances. This 



204 VARNISHES. 

coloured varnish will produce a very striking effect 
in japanned goods, paper-hangings, &c, and can be 
made at a very cheap rate. 



ETCHING VARNISH. 

Take of white wax, two ounces ; and of black 
and Burgundy pitch, each half an ounce. Melt to- 
gether, adding by degrees two ounces of powdered 
asphaltum. Then boil until a drop taken out on a 
plate will break when cold, by being bent double 
two or three times between the fingers, when it must 
be poured into warm water, and made into small 
balls for use. 



THE END. 



V* 






A 









■ 

*V 















U * a 


































































o' 






-.^, 
























SEP 7 6 






